diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 5a1c13d6781..676e885c0bb 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -53,7 +53,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
       visibility: visibility_from_audience,
       thread: replied_to_status,
       conversation: conversation_from_uri(@object['conversation']),
-      media_attachments: process_attachments.take(4),
+      media_attachment_ids: process_attachments.take(4).map(&:id),
     }
   end
 
diff --git a/app/lib/ostatus/activity/creation.rb b/app/lib/ostatus/activity/creation.rb
index aa46267dc71..6235127b206 100644
--- a/app/lib/ostatus/activity/creation.rb
+++ b/app/lib/ostatus/activity/creation.rb
@@ -45,7 +45,7 @@ class OStatus::Activity::Creation < OStatus::Activity::Base
         visibility: visibility_scope,
         conversation: find_or_create_conversation,
         thread: thread? ? find_status(thread.first) || find_activitypub_status(thread.first, thread.second) : nil,
-        media_attachments: media_attachments
+        media_attachment_ids: media_attachments.map(&:id)
       )
 
       save_mentions(status)