1 files changed, 1 insertions, 1 deletions
diff --git a/actionmailer/lib/action_mailer/helpers.rb b/actionmailer/lib/action_mailer/helpers.rb
index 7f20efb3c6..3e5ed9e9d7 100644
--- a/actionmailer/lib/action_mailer/helpers.rb
+++ b/actionmailer/lib/action_mailer/helpers.rb
@@ -95,7 +95,7 @@ module ActionMailer
             child.master_helper_module.send! :include, master_helper_module
             child.helper child.name.to_s.underscore
           rescue MissingSourceFile => e
-            raise unless e.is_missing?("helpers/#{child.name.underscore}_helper")
+            raise unless e.is_missing?("helpers/#{child.name.to_s.underscore}_helper")
           end
         end
     end