diff --git a/plone/app/discussion/TODO.txt b/plone/app/discussion/TODO.txt
index a1c8318..af79d25 100644
--- a/plone/app/discussion/TODO.txt
+++ b/plone/app/discussion/TODO.txt
@@ -17,7 +17,7 @@ plone.app.discussion to-do
 
  [ ] Add i18n translations
 
- [ ] Add id fall back for Creator if no Username (Title) has been added
+ [X] Add id fall back for Creator if no Username (Title) has been added
 
  [ ] Plone reports "unsuccessfully attempted to uncatalog an object" while
      trying to delete a comment.
diff --git a/plone/app/discussion/browser/comments.py b/plone/app/discussion/browser/comments.py
index c339ec8..078d0b2 100644
--- a/plone/app/discussion/browser/comments.py
+++ b/plone/app/discussion/browser/comments.py
@@ -158,7 +158,11 @@ class AddComment(BrowserView):
                 comment.creation_date = comment.modification_date = datetime.now()
             else:
                 member = portal_membership.getAuthenticatedMember()
-                comment.creator = member.getProperty('fullname')
+                fullname = member.getProperty('fullname')
+                if fullname == '' or None:
+                    comment.creator = member.id
+                else:
+                    comment.creator = fullname
                 comment.author_username = member.getUserName()
                 comment.author_name = member.getProperty('fullname')
                 comment.author_email = member.getProperty('email')