diff --git a/package/src/components/MessageInput/__tests__/AttachmentUploadPreviewList.test.tsx b/package/src/components/MessageInput/__tests__/AttachmentUploadPreviewList.test.tsx
index 0f1053a760..0556e70e2f 100644
--- a/package/src/components/MessageInput/__tests__/AttachmentUploadPreviewList.test.tsx
+++ b/package/src/components/MessageInput/__tests__/AttachmentUploadPreviewList.test.tsx
@@ -652,5 +652,29 @@ describe('AttachmentUploadPreviewList', () => {
         expect(screen.queryAllByTestId('image-attachment-upload-preview')).toHaveLength(1);
       });
     });
+
+    it('shows the duration a sent video carries in custom.duration', async () => {
+      const custom = { duration: 125000, mime_type: 'video/mp4' };
+
+      act(() => {
+        channel.messageComposer.initState({
+          composition: generateMessage({
+            attachments: [
+              generateVideoAttachmentBase({
+                asset_url: 'https://video-attachment.mp4',
+                custom,
+                thumb_url: 'https://video-attachment-thumb.png',
+              }),
+            ],
+          }),
+        });
+      });
+
+      renderComponent({ channel, client, props: {} });
+
+      await waitFor(() => {
+        expect(screen.getByText('2m')).toBeTruthy();
+      });
+    });
   });
 });
diff --git a/package/src/components/MessageInput/components/AttachmentPreview/VideoAttachmentUploadPreview.tsx b/package/src/components/MessageInput/components/AttachmentPreview/VideoAttachmentUploadPreview.tsx
index 7a74540a12..77e862d119 100644
--- a/package/src/components/MessageInput/components/AttachmentPreview/VideoAttachmentUploadPreview.tsx
+++ b/package/src/components/MessageInput/components/AttachmentPreview/VideoAttachmentUploadPreview.tsx
@@ -29,7 +29,13 @@ export const VideoAttachmentUploadPreview = ({
   // `localMetadata.file` is `File | FileReference`; only the RN `FileReference` carries a
   // `duration` (and a required `uri` to discriminate on), so read it through a guard.
   const localFile = attachment.localMetadata.file;
-  const duration = localFile && 'uri' in localFile ? localFile.duration : undefined;
+  const { custom } = attachment;
+  const duration =
+    localFile && 'uri' in localFile
+      ? localFile.duration
+      : custom && 'duration' in custom && typeof custom.duration === 'number'
+        ? custom.duration
+        : undefined;
 
   return previewUri ? (
     <>
diff --git a/package/src/middlewares/__tests__/attachments.test.ts b/package/src/middlewares/__tests__/attachments.test.ts
index 395fd00635..51927cdf99 100644
--- a/package/src/middlewares/__tests__/attachments.test.ts
+++ b/package/src/middlewares/__tests__/attachments.test.ts
@@ -81,6 +81,29 @@ describe('setupVideoAttachmentPreviewMiddleware', () => {
     expect(state.attachment.localMetadata.previewUri).toBeUndefined();
   });
 
+  it('sends the picked file duration along as custom.duration', () => {
+    const { next } = runPrepare(
+      localVideoAttachment({
+        custom: { mime_type: 'video/mp4' },
+        localMetadata: {
+          file: { duration: 125000, name: 'clip.mp4', uri: 'file://local/clip.mp4' },
+          id: 'clip',
+          uploadState: 'uploading',
+        },
+      }),
+    );
+
+    const state = next.mock.calls[0][0] as { attachment: LocalAttachment };
+    expect(state.attachment.custom).toEqual({ duration: 125000, mime_type: 'video/mp4' });
+  });
+
+  it('leaves custom untouched when the picked file has no duration', () => {
+    const { next } = runPrepare(localVideoAttachment({ custom: { mime_type: 'video/mp4' } }));
+
+    const state = next.mock.calls[0][0] as { attachment: LocalAttachment };
+    expect(state.attachment.custom).toEqual({ mime_type: 'video/mp4' });
+  });
+
   it('forwards anything that is not a local video', () => {
     const image = runPrepare(
       localVideoAttachment({ image_url: 'file://local/photo.jpg', type: 'image' }),
diff --git a/package/src/middlewares/attachments.ts b/package/src/middlewares/attachments.ts
index 41d5e7c1cb..00dea363a8 100644
--- a/package/src/middlewares/attachments.ts
+++ b/package/src/middlewares/attachments.ts
@@ -6,7 +6,9 @@ import {
 
 /**
  * Sets a local video's `localMetadata.previewUri` to its `thumb_url`, because the picked video
- * file itself cannot be rendered as a preview (other attachments preview the file URI).
+ * file itself cannot be rendered as a preview (other attachments preview the file URI). Also sends
+ * the picked file's duration along as `custom.duration`, since the local file is gone once the
+ * message is sent (e.g. when editing it).
  */
 const createVideoAttachmentPreviewMiddleware = (): AttachmentPreUploadMiddleware => ({
   id: 'stream-io/message-composer-ui-middleware/video-attachment-preview',
@@ -18,10 +20,16 @@ const createVideoAttachmentPreviewMiddleware = (): AttachmentPreUploadMiddleware
         return forward();
       }
 
+      // Only the RN `FileReference` carries a `duration` (and a required `uri` to discriminate on).
+      const { file } = attachment.localMetadata;
+      const duration = file && 'uri' in file ? file.duration : undefined;
+      const custom = duration ? { ...attachment.custom, duration } : attachment.custom;
+
       return next({
         ...state,
         attachment: {
           ...attachment,
+          custom,
           localMetadata: {
             ...attachment.localMetadata,
             previewUri: attachment.thumb_url,