diff --git a/modules/API/API.js b/modules/API/API.js
index 0b06fa2d9..55d3908b1 100644
--- a/modules/API/API.js
+++ b/modules/API/API.js
@@ -21,7 +21,7 @@ import {
 import { isEnabled as isDropboxEnabled } from '../../react/features/dropbox';
 import { toggleE2EE } from '../../react/features/e2ee/actions';
 import { invite } from '../../react/features/invite';
-import { selectParticipantInLargeVideo } from '../../react/features/large-video/actions';
+import { resizeLargeVideo, selectParticipantInLargeVideo } from '../../react/features/large-video/actions';
 import { toggleLobbyMode } from '../../react/features/lobby/actions.web';
 import { RECORDING_TYPES } from '../../react/features/recording/constants';
 import { getActiveSession } from '../../react/features/recording/functions';
@@ -119,6 +119,11 @@ function initCommands() {
         'proxy-connection-event': event => {
             APP.conference.onProxyConnectionEvent(event);
         },
+        'resize-large-video': (width, height) => {
+            logger.debug('Resize large video command received');
+            sendAnalytics(createApiEvent('largevideo.resized'));
+            APP.store.dispatch(resizeLargeVideo(width, height));
+        },
         'send-tones': (options = {}) => {
             const { duration, tones, pause } = options;
 
diff --git a/modules/API/external/external_api.js b/modules/API/external/external_api.js
index 5f192f00e..895b8a3a9 100644
--- a/modules/API/external/external_api.js
+++ b/modules/API/external/external_api.js
@@ -35,6 +35,7 @@ const commands = {
     hangup: 'video-hangup',
     muteEveryone: 'mute-everyone',
     password: 'password',
+    resizeLargeVideo: 'resize-large-video',
     sendEndpointTextMessage: 'send-endpoint-text-message',
     sendTones: 'send-tones',
     setLargeVideoParticipant: 'set-large-video-participant',
@@ -437,10 +438,12 @@ export default class JitsiMeetExternalAPI extends EventEmitter {
         const parsedWidth = parseSizeParam(width);
 
         if (parsedHeight !== undefined) {
+            this._height = height;
             this._frame.style.height = parsedHeight;
         }
 
         if (parsedWidth !== undefined) {
+            this._width = width;
             this._frame.style.width = parsedWidth;
         }
     }
@@ -930,6 +933,19 @@ export default class JitsiMeetExternalAPI extends EventEmitter {
         eventList.forEach(event => this.removeEventListener(event));
     }
 
+    /**
+     * Resizes the large video container as per the dimensions provided.
+     *
+     * @param {number} width - Width that needs to be applied on the large video container.
+     * @param {number} height - Height that needs to be applied on the large video container.
+     * @returns {void}
+     */
+    resizeLargeVideo(width, height) {
+        if (width <= this._width && height <= this._height) {
+            this.executeCommand('resizeLargeVideo', width, height);
+        }
+    }
+
     /**
      * Passes an event along to the local conference participant to establish
      * or update a direct peer connection. This is currently used for developing
diff --git a/modules/UI/util/UIUtil.js b/modules/UI/util/UIUtil.js
index 30e8b6ede..d70bbe983 100644
--- a/modules/UI/util/UIUtil.js
+++ b/modules/UI/util/UIUtil.js
@@ -5,13 +5,6 @@
  */
 const UIUtil = {
 
-    /**
-     * Returns the available video width.
-     */
-    getAvailableVideoWidth() {
-        return window.innerWidth;
-    },
-
     /**
      * Escapes the given text.
      */
diff --git a/modules/UI/videolayout/LargeVideoManager.js b/modules/UI/videolayout/LargeVideoManager.js
index da16533ea..98f236b39 100644
--- a/modules/UI/videolayout/LargeVideoManager.js
+++ b/modules/UI/videolayout/LargeVideoManager.js
@@ -21,7 +21,6 @@ import { PresenceLabel } from '../../../react/features/presence-status';
 import UIEvents from '../../../service/UI/UIEvents';
 import { createDeferred } from '../../util/helpers';
 import AudioLevels from '../audio_levels/AudioLevels';
-import UIUtil from '../util/UIUtil';
 
 import { VideoContainer, VIDEO_CONTAINER_TYPE } from './VideoContainer';
 
@@ -323,20 +322,25 @@ export default class LargeVideoManager {
     /**
      * Update container size.
      */
-    updateContainerSize() {
-        let widthToUse = UIUtil.getAvailableVideoWidth();
+    updateContainerSize(width, height) {
+        let widthToUse = width ?? (this.width > 0 ? this.width : window.innerWidth);
         const { isOpen } = APP.store.getState()['features/chat'];
 
+        /**
+         * If chat state is open, we re-compute the container width by subtracting the default width of
+         * the chat. We re-compute the width again after the chat window is closed. This is needed when
+         * custom styling is configured on the large video container through the iFrame API.
+         */
         if (isOpen) {
-            /**
-             * If chat state is open, we re-compute the container width
-             * by subtracting the default width of the chat.
-             */
             widthToUse -= CHAT_SIZE;
+            this.resizedForChat = true;
+        } else if (this.resizedForChat) {
+            this.resizedForChat = false;
+            widthToUse += CHAT_SIZE;
         }
 
         this.width = widthToUse;
-        this.height = window.innerHeight;
+        this.height = height ?? (this.height > 0 ? this.height : window.innerHeight);
     }
 
     /**
diff --git a/react/features/large-video/actions.js b/react/features/large-video/actions.js
index eb645b975..9100403c4 100644
--- a/react/features/large-video/actions.js
+++ b/react/features/large-video/actions.js
@@ -2,6 +2,7 @@
 
 import type { Dispatch } from 'redux';
 
+import VideoLayout from '../../../modules/UI/videolayout/VideoLayout';
 import {
     createSelectParticipantFailedEvent,
     sendAnalytics
@@ -19,6 +20,27 @@ import {
 
 declare var APP: Object;
 
+/**
+ * Resizes the large video container based on the dimensions provided.
+ *
+ * @param {number} width - Width that needs to be applied on the large video container.
+ * @param {number} height - Height that needs to be applied on the large video container.
+ * @returns {void}
+ */
+export function resizeLargeVideo(width: number, height: number) {
+    return (dispatch: Dispatch<any>, getState: Function) => {
+        const state = getState();
+        const largeVideo = state['features/large-video'];
+
+        if (largeVideo) {
+            const largeVideoContainer = VideoLayout.getLargeVideo();
+
+            largeVideoContainer.updateContainerSize(width, height);
+            largeVideoContainer.resize();
+        }
+    };
+}
+
 /**
  * Signals conference to select a participant.
  *