diff --git a/app/serializers/post_action_user_serializer.rb b/app/serializers/post_action_user_serializer.rb
index 72dbd8e4d82..7a63768f00a 100644
--- a/app/serializers/post_action_user_serializer.rb
+++ b/app/serializers/post_action_user_serializer.rb
@@ -1,5 +1,6 @@
 class PostActionUserSerializer < BasicUserSerializer
-  attributes :post_url
+  attributes :post_url,
+             :username_lower
 
   def id
     object.user.id
@@ -9,6 +10,10 @@ class PostActionUserSerializer < BasicUserSerializer
     object.user.username
   end
 
+  def username_lower
+    object.user.username_lower
+  end
+
   def avatar_template
     object.user.avatar_template
   end