diff --git a/cypress/e2e/audio-player/audio-player.spec.ts b/cypress/e2e/audio-player/audio-player.spec.ts
new file mode 100644
index 00000000000..ef908ed2920
--- /dev/null
+++ b/cypress/e2e/audio-player/audio-player.spec.ts
@@ -0,0 +1,389 @@
+/*
+Copyright 2023 Suguru Hirahara
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/// <reference types="cypress" />
+
+import { HomeserverInstance } from "../../plugins/utils/homeserver";
+import { SettingLevel } from "../../../src/settings/SettingLevel";
+import { Layout } from "../../../src/settings/enums/Layout";
+
+describe("Audio player", () => {
+    let homeserver: HomeserverInstance;
+    const TEST_USER = "Hanako";
+
+    const percyCSS =
+        // FIXME: hide mx_SeekBar because flaky - see https://github.com/vector-im/element-web/issues/24898
+        ".mx_SeekBar, " +
+        // Exclude various components from the snapshot, for consistency
+        ".mx_JumpToBottomButton, " +
+        ".mx_MessageTimestamp, .mx_RoomView_myReadMarker { visibility: hidden !important; }";
+
+    const uploadFile = (file: string) => {
+        // Upload a file from the message composer
+        cy.get(".mx_MessageComposer_actions input[type='file']").selectFile(file, { force: true });
+
+        cy.get(".mx_Dialog").within(() => {
+            // Find and click primary "Upload" button
+            cy.get("[data-testid='dialog-primary-button']").findButton("Upload").click();
+        });
+
+        // Wait until the file is sent
+        cy.get(".mx_RoomView_statusArea_expanded").should("not.exist");
+        cy.get(".mx_EventTile.mx_EventTile_last .mx_EventTile_receiptSent").should("exist");
+    };
+
+    /**
+     * Take snapshots of mx_EventTile_last on each layout, outputting log for reference/debugging.
+     * @param detail The Percy snapshot name. Used for outputting logs too.
+     * @param monospace This changes the font used to render the UI from a default one to a monospace one.
+     * Set to false by default. Note that the font applied to Percy snapshots can be different from the test result
+     * on your local environment.
+     */
+    const takeSnapshots = (detail: string, monospace = false) => {
+        // Check that the audio player is rendered and its button becomes visible
+        const checkPlayerVisibility = () => {
+            // Assert that the audio player and media information are visible
+            cy.get(".mx_EventTile_mediaLine .mx_MAudioBody .mx_AudioPlayer_container .mx_AudioPlayer_mediaInfo").within(
+                () => {
+                    cy.contains(".mx_AudioPlayer_mediaName", ".ogg").should("be.visible"); // extension
+                    cy.contains(".mx_AudioPlayer_byline", "00:01").should("be.visible");
+                    cy.contains(".mx_AudioPlayer_byline", "(3.56 KB)").should("be.visible"); // actual size
+                },
+            );
+
+            // Assert that the play button can be found and is visible
+            cy.findButton("Play").should("be.visible");
+
+            if (monospace) {
+                // Assert that the monospace timer is visible
+                cy.get("[role='timer']").should("have.css", "font-family", '"monospace"').should("be.visible");
+            }
+        };
+
+        /**
+         * Define snapshot widths of selected EventTile, on which the audio player is rendered
+         *
+         * 50px (magic number): narrow enough EventTile to be compressed to check a11y
+         * 267px: EventTile on IRC and modern/group layout, on which the player is rendered in its full width
+         * 285px: EventTile on bubble layout, on which the player is rendered in its full width
+         */
+        const snapshotWidthsIRC = [50, 267];
+        const snapshotWidthsGroup = snapshotWidthsIRC;
+        const snapshotWidthsBubble = [50, 285];
+
+        if (monospace) {
+            // Enable system font and monospace setting
+            cy.setSettingValue("useSystemFont", null, SettingLevel.DEVICE, true);
+            cy.setSettingValue("systemFont", null, SettingLevel.DEVICE, "monospace");
+        }
+
+        // Check the status of the seek bar
+        // TODO: check if visible - currently checking its visibility on a compressed EventTile returns an error
+        cy.get(".mx_AudioPlayer_seek input[type='range']").should("exist");
+
+        // Enable IRC layout
+        cy.setSettingValue("layout", null, SettingLevel.DEVICE, Layout.IRC);
+
+        cy.get(".mx_EventTile_last[data-layout='irc']").within(() => {
+            // Click the event timestamp to highlight EventTile in case it is not visible
+            cy.get(".mx_MessageTimestamp").click();
+
+            // Assert that rendering of the player settled and the play button is visible before taking a snapshot
+            checkPlayerVisibility();
+        });
+
+        // Take a snapshot of mx_EventTile_last on IRC layout
+        cy.get(".mx_EventTile_last").percySnapshotElement(detail + " on IRC layout", {
+            percyCSS,
+            widths: snapshotWidthsIRC,
+        });
+
+        // Output a log
+        cy.log("Took a snapshot of " + detail + " on IRC layout");
+
+        // Take a snapshot on modern/group layout
+        cy.setSettingValue("layout", null, SettingLevel.DEVICE, Layout.Group);
+        cy.get(".mx_EventTile_last[data-layout='group']").within(() => {
+            cy.get(".mx_MessageTimestamp").click();
+            checkPlayerVisibility();
+        });
+        cy.get(".mx_EventTile_last").percySnapshotElement(detail + " on modern/group layout", {
+            percyCSS,
+            widths: snapshotWidthsGroup,
+        });
+        cy.log("Took a snapshot of " + detail + " on modern/group layout");
+
+        // Take a snapshot on bubble layout
+        cy.setSettingValue("layout", null, SettingLevel.DEVICE, Layout.Bubble);
+        cy.get(".mx_EventTile_last[data-layout='bubble']").within(() => {
+            cy.get(".mx_MessageTimestamp").click();
+            checkPlayerVisibility();
+        });
+        cy.get(".mx_EventTile_last").percySnapshotElement(detail + " on bubble layout", {
+            percyCSS,
+            widths: snapshotWidthsBubble,
+        });
+        cy.log("Took a snapshot of " + detail + " on bubble layout");
+    };
+
+    beforeEach(() => {
+        cy.startHomeserver("default").then((data) => {
+            homeserver = data;
+            cy.initTestUser(homeserver, TEST_USER);
+        });
+
+        cy.createRoom({ name: "Test Room" }).viewRoomByName("Test Room");
+
+        // Wait until configuration is finished
+        cy.contains(
+            ".mx_RoomView_body .mx_GenericEventListSummary[data-layout='group'] .mx_GenericEventListSummary_summary",
+            "created and configured the room.",
+        ).should("exist");
+    });
+
+    afterEach(() => {
+        cy.stopHomeserver(homeserver);
+    });
+
+    it("should be correctly rendered - light theme", () => {
+        uploadFile("cypress/fixtures/1sec-long-name-audio-file.ogg");
+
+        takeSnapshots("Selected EventTile of audio player (light theme)");
+    });
+
+    it("should be correctly rendered - light theme with monospace font", () => {
+        uploadFile("cypress/fixtures/1sec-long-name-audio-file.ogg");
+
+        takeSnapshots("Selected EventTile of audio player (light theme, monospace font)", true); // Enable monospace
+    });
+
+    it("should be correctly rendered - high contrast theme", () => {
+        // Disable system theme in case ThemeWatcher enables the theme automatically,
+        // so that the high contrast theme can be enabled
+        cy.setSettingValue("use_system_theme", null, SettingLevel.DEVICE, false);
+
+        // Enable high contrast manually
+        cy.openUserSettings("Appearance")
+            .get(".mx_ThemeChoicePanel")
+            .within(() => {
+                cy.get("[data-testid='theme-choice-panel-selectors']").within(() => {
+                    // Enable light theme
+                    cy.get(".mx_ThemeSelector_light").click();
+
+                    // Assert that the radio button for light theme was checked
+                    cy.get(".mx_StyledRadioButton_checked input[value='light']").should("exist");
+                });
+
+                cy.get("[data-testid='theme-choice-panel-highcontrast']").within(() => {
+                    // Click the checkbox
+                    cy.get("label .mx_Checkbox_background").click();
+                });
+            });
+
+        cy.closeDialog();
+
+        uploadFile("cypress/fixtures/1sec-long-name-audio-file.ogg");
+
+        takeSnapshots("Selected EventTile of audio player (high contrast)");
+    });
+
+    it("should be correctly rendered - dark theme", () => {
+        // Enable dark theme
+        cy.setSettingValue("theme", null, SettingLevel.ACCOUNT, "dark");
+
+        uploadFile("cypress/fixtures/1sec-long-name-audio-file.ogg");
+
+        takeSnapshots("Selected EventTile of audio player (dark theme)");
+    });
+
+    it("should play an audio file", () => {
+        uploadFile("cypress/fixtures/1sec.ogg");
+
+        // Assert that the audio player is rendered
+        cy.get(".mx_EventTile_last .mx_EventTile_mediaLine .mx_MAudioBody .mx_AudioPlayer_container").within(() => {
+            // Assert that the counter is zero before clicking the play button
+            cy.contains(".mx_AudioPlayer_seek [role='timer']", "00:00").should("exist");
+
+            // Find and click "Play" button
+            cy.findButton("Play").click();
+
+            // Assert that "Pause" button can be found
+            cy.findButton("Pause").should("exist");
+
+            // Assert that the timer is reset when the audio file finished playing
+            cy.contains(".mx_AudioPlayer_seek [role='timer']", "00:00").should("exist");
+
+            // Assert that "Play" button can be found
+            cy.findButton("Play").should("exist");
+        });
+    });
+
+    it("should support downloading an audio file", () => {
+        uploadFile("cypress/fixtures/1sec.ogg");
+
+        // Find and click "Download" button on MessageActionBar
+        cy.get(".mx_EventTile_last").realHover().findButton("Download").click();
+
+        // Assert that the file was downloaded
+        cy.readFile("cypress/downloads/1sec.ogg").should("exist");
+    });
+
+    it("should support replying to audio file with another audio file", () => {
+        uploadFile("cypress/fixtures/1sec.ogg");
+
+        // Assert the audio player is rendered
+        cy.get(".mx_EventTile_last .mx_AudioPlayer_container").should("exist");
+
+        // Find and click "Reply" button on MessageActionBar
+        cy.get(".mx_EventTile_last").realHover().findButton("Reply").click();
+
+        // Reply to the player with another audio file
+        uploadFile("cypress/fixtures/1sec.ogg");
+
+        cy.get(".mx_EventTile_last").within(() => {
+            // Assert that the audio player is rendered
+            cy.get(".mx_AudioPlayer_container").should("exist");
+
+            // Assert that replied audio file is rendered as file button inside ReplyChain
+            cy.get(".mx_ReplyChain_wrapper .mx_MFileBody_info[role='button']").within(() => {
+                // Assert that the file button has file name
+                cy.get(".mx_MFileBody_info_filename").should("exist");
+            });
+        });
+
+        // Take snapshots
+        takeSnapshots("Selected EventTile of audio player with a reply");
+    });
+
+    it("should support creating a reply chain with multiple audio files", () => {
+        // Note: "mx_ReplyChain" element is used not only for replies which
+        // create a reply chain, but also for a single reply without a replied
+        // message. This test checks whether a reply chain which consists of
+        // multiple audio file replies is rendered properly.
+
+        // Find and click "Reply" button
+        const clickButtonReply = () => {
+            cy.get(".mx_EventTile_last").realHover().findButton("Reply").click();
+        };
+
+        uploadFile("cypress/fixtures/upload-first.ogg");
+
+        // Assert that the audio player is rendered
+        cy.get(".mx_EventTile_last .mx_AudioPlayer_container").should("exist");
+
+        clickButtonReply();
+
+        // Reply to the player with another audio file
+        uploadFile("cypress/fixtures/upload-second.ogg");
+
+        // Assert that the audio player is rendered
+        cy.get(".mx_EventTile_last .mx_AudioPlayer_container").should("exist");
+
+        clickButtonReply();
+
+        // Reply to the player with yet another audio file to create a reply chain
+        uploadFile("cypress/fixtures/upload-third.ogg");
+
+        cy.get(".mx_EventTile_last").within(() => {
+            // Assert that the audio player is rendered
+            cy.get(".mx_AudioPlayer_container").should("exist");
+
+            // Assert that there are two "mx_ReplyChain" elements
+            cy.get(".mx_ReplyChain").should("have.length", 2);
+
+            // Assert that one line contains the user name
+            cy.contains(".mx_ReplyChain .mx_ReplyTile_sender", TEST_USER);
+
+            // Assert that the other line contains the file button
+            cy.get(".mx_ReplyChain .mx_MFileBody").should("exist");
+
+            // Click "In reply to"
+            cy.contains(".mx_ReplyChain .mx_ReplyChain_show", "In reply to").click();
+
+            cy.get("blockquote.mx_ReplyChain:first-of-type").within(() => {
+                // Assert that "In reply to" has disappeared
+                cy.contains("In reply to").should("not.exist");
+
+                // Assert that audio file on the first row is rendered as file button
+                cy.get(".mx_MFileBody_info[role='button']").within(() => {
+                    // Assert that the file button contains the name of the file sent at first
+                    cy.contains(".mx_MFileBody_info_filename", "upload-first.ogg");
+                });
+            });
+        });
+
+        // Take snapshots
+        takeSnapshots("Selected EventTile of audio player with a reply chain");
+    });
+
+    it("should be rendered, play, and support replying on a thread", () => {
+        uploadFile("cypress/fixtures/1sec-long-name-audio-file.ogg");
+
+        // On the main timeline
+        cy.get(".mx_RoomView_MessageList").within(() => {
+            // Assert the audio player is rendered
+            cy.get(".mx_EventTile_last .mx_AudioPlayer_container").should("exist");
+
+            // Find and click "Reply in thread" button
+            cy.get(".mx_EventTile_last").realHover().findButton("Reply in thread").click();
+        });
+
+        // On a thread
+        cy.get(".mx_ThreadView").within(() => {
+            cy.get(".mx_EventTile_last")
+                .within(() => {
+                    // Assert that the player is correctly rendered on a thread
+                    cy.get(".mx_EventTile_mediaLine .mx_MAudioBody .mx_AudioPlayer_container").within(() => {
+                        // Assert that the counter is zero before clicking the play button
+                        cy.contains(".mx_AudioPlayer_seek [role='timer']", "00:00").should("exist");
+
+                        // Find and click "Play" button
+                        cy.findButton("Play").click();
+
+                        // Assert that "Pause" button can be found
+                        cy.findButton("Pause").should("exist");
+
+                        // Assert that the timer is reset when the audio file finished playing
+                        cy.contains(".mx_AudioPlayer_seek [role='timer']", "00:00").should("exist");
+
+                        // Assert that "Play" button can be found
+                        cy.findButton("Play").should("exist");
+                    });
+                })
+                .realHover()
+                .findButton("Reply")
+                .click(); // Find and click "Reply" button
+
+            cy.get(".mx_MessageComposer--compact").within(() => {
+                // Assert that the reply preview is rendered on the message composer
+                cy.get(".mx_ReplyPreview").within(() => {
+                    // Assert that the reply preview contains audio ReplyTile the file info button
+                    cy.get(".mx_ReplyTile_audio .mx_MFileBody_info[role='button']").should("exist");
+                });
+
+                // Select :smile: emoji and send it
+                cy.get("[data-testid='basicmessagecomposer']").type(":smile:");
+                cy.get(".mx_Autocomplete_Completion[aria-selected='true']").click();
+                cy.get("[data-testid='basicmessagecomposer']").type("{enter}");
+            });
+
+            cy.get(".mx_EventTile_last").within(() => {
+                // Assert that the file name is rendered on the file button
+                cy.get(".mx_ReplyTile_audio .mx_MFileBody_info[role='button']").should("exist");
+            });
+        });
+    });
+});
diff --git a/cypress/fixtures/1sec-long-name-audio-file.ogg b/cypress/fixtures/1sec-long-name-audio-file.ogg
new file mode 100755
index 00000000000..a8b078e1694
Binary files /dev/null and b/cypress/fixtures/1sec-long-name-audio-file.ogg differ
diff --git a/cypress/fixtures/upload-first.ogg b/cypress/fixtures/upload-first.ogg
new file mode 100755
index 00000000000..a8b078e1694
Binary files /dev/null and b/cypress/fixtures/upload-first.ogg differ
diff --git a/cypress/fixtures/upload-second.ogg b/cypress/fixtures/upload-second.ogg
new file mode 100755
index 00000000000..a8b078e1694
Binary files /dev/null and b/cypress/fixtures/upload-second.ogg differ
diff --git a/cypress/fixtures/upload-third.ogg b/cypress/fixtures/upload-third.ogg
new file mode 100755
index 00000000000..a8b078e1694
Binary files /dev/null and b/cypress/fixtures/upload-third.ogg differ
diff --git a/src/components/views/settings/ThemeChoicePanel.tsx b/src/components/views/settings/ThemeChoicePanel.tsx
index df769a9456f..32c411cd77e 100644
--- a/src/components/views/settings/ThemeChoicePanel.tsx
+++ b/src/components/views/settings/ThemeChoicePanel.tsx
@@ -168,7 +168,7 @@ export default class ThemeChoicePanel extends React.Component<IProps, IState> {
             (findHighContrastTheme(this.state.theme) || isHighContrastTheme(this.state.theme))
         ) {
             return (
-                <div>
+                <div data-testid="theme-choice-panel-highcontrast">
                     <StyledCheckbox
                         checked={isHighContrastTheme(this.state.theme)}
                         onChange={(e) => this.highContrastThemeChanged(e.target.checked)}
@@ -248,7 +248,7 @@ export default class ThemeChoicePanel extends React.Component<IProps, IState> {
             <div className="mx_SettingsTab_section mx_ThemeChoicePanel">
                 <span className="mx_SettingsTab_subheading">{_t("Theme")}</span>
                 {systemThemeSection}
-                <div className="mx_ThemeSelectors">
+                <div className="mx_ThemeSelectors" data-testid="theme-choice-panel-selectors">
                     <StyledRadioGroup
                         name="theme"
                         definitions={orderedThemes.map((t) => ({
diff --git a/test/components/views/settings/__snapshots__/ThemeChoicePanel-test.tsx.snap b/test/components/views/settings/__snapshots__/ThemeChoicePanel-test.tsx.snap
index b1bd41e8f5d..2ee7d3d4dfa 100644
--- a/test/components/views/settings/__snapshots__/ThemeChoicePanel-test.tsx.snap
+++ b/test/components/views/settings/__snapshots__/ThemeChoicePanel-test.tsx.snap
@@ -12,6 +12,7 @@ exports[`ThemeChoicePanel renders the theme choice UI 1`] = `
     </span>
     <div
       class="mx_ThemeSelectors"
+      data-testid="theme-choice-panel-selectors"
     >
       <label
         class="mx_StyledRadioButton mx_ThemeSelector_light mx_StyledRadioButton_disabled mx_StyledRadioButton_outlined"