diff --git a/mautrix_telegram/portal.py b/mautrix_telegram/portal.py
index 2d7c0a57..2e4dfe38 100644
--- a/mautrix_telegram/portal.py
+++ b/mautrix_telegram/portal.py
@@ -1257,6 +1257,12 @@ class Portal:
                 self.db.commit()
             return
 
+        if sender and not sender.displayname:
+            self.log.debug(f"Telegram user {sender.tgid} sent a message, but doesn't have a"
+                           "displayname, updating info...")
+            entity = await source.client.get_entity(PeerUser(sender.tgid))
+            await sender.update_info(source, entity)
+
         allowed_media = (MessageMediaPhoto, MessageMediaDocument, MessageMediaGeo)
         media = evt.media if hasattr(evt, "media") and isinstance(evt.media,
                                                                   allowed_media) else None