diff --git a/app/models/answer.rb b/app/models/answer.rb
index 83b82918..d05e16a4 100644
--- a/app/models/answer.rb
+++ b/app/models/answer.rb
@@ -10,7 +10,7 @@ class Answer < ActiveRecord::Base
 
     Notification.notify self.question.user, self unless self.question.author_is_anonymous
     Subscription.subscribe self.user, self
-    Subscription.subscribe self.question.user, self
+    Subscription.subscribe self.question.user, self unless self.question.user.nil?
     self.user.increment! :answered_count
     self.question.increment! :answer_count
   end