diff --git a/src/components/views/rooms/EventTile.tsx b/src/components/views/rooms/EventTile.tsx
index a860d48ac9..d816c02769 100644
--- a/src/components/views/rooms/EventTile.tsx
+++ b/src/components/views/rooms/EventTile.tsx
@@ -360,6 +360,7 @@ interface IState {
     thread: Thread;
     threadReplyCount: number;
     threadLastReply: MatrixEvent;
+    threadLastSender: RoomMember | null;
     threadNotification?: NotificationCountType;
 }
 
@@ -408,6 +409,7 @@ export default class EventTile extends React.Component<IProps, IState> {
             thread,
             threadReplyCount: thread?.length,
             threadLastReply: thread?.replyToEvent,
+            threadLastSender: thread?.replyToEvent.sender,
         };
 
         // don't do RR animations until we are mounted
@@ -562,6 +564,7 @@ export default class EventTile extends React.Component<IProps, IState> {
 
         this.setState({
             threadLastReply: thread?.replyToEvent,
+            threadLastSender: thread?.replyToEvent?.sender,
             threadReplyCount: thread?.length,
             thread,
         });
@@ -659,23 +662,24 @@ export default class EventTile extends React.Component<IProps, IState> {
 
     private renderThreadLastMessagePreview(): JSX.Element | null {
         const { threadLastReply } = this.state;
-        if (!threadLastReply) {
-            return null;
-        }
-
         const threadMessagePreview = MessagePreviewStore.instance.generatePreviewForEvent(threadLastReply);
 
-        if (!threadMessagePreview || !threadLastReply.sender) {
-            return null;
-        }
-
+        const sender = this.thread.roomState.getSentinelMember(threadLastReply.getSender());
         return <>
-            <MemberAvatar member={threadLastReply.sender} width={24} height={24} className="mx_ThreadInfo_avatar" />
-            <div className="mx_ThreadInfo_content">
-                <span className="mx_ThreadInfo_message-preview">
-                    { threadMessagePreview }
-                </span>
-            </div>
+            <MemberAvatar
+                member={sender}
+                fallbackUserId={threadLastReply.getSender()}
+                width={24}
+                height={24}
+                className="mx_ThreadInfo_avatar"
+            />
+            { threadMessagePreview && (
+                <div className="mx_ThreadInfo_content">
+                    <span className="mx_ThreadInfo_message-preview">
+                        { threadMessagePreview }
+                    </span>
+                </div>
+            ) }
         </>;
     }