diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 1676c23856a..a96cbd7871f 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -381,7 +381,7 @@ module ActionMailer #:nodoc:
 
     self.protected_instance_variables = [:@_action_has_layout]
 
-    helper  ActionMailer::MailHelper
+    helper ActionMailer::MailHelper
 
     private_class_method :new #:nodoc: