diff --git a/actionmailer/CHANGELOG.md b/actionmailer/CHANGELOG.md
index ab93745f602fdceccf237ba0c30e5f134cd6a8f0..451270bae3d5ff94ce12e1b7edc2c7049bc61b75 100644
--- a/actionmailer/CHANGELOG.md
+++ b/actionmailer/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Make ActionMailer::Previews methods class methods. Previously they were
+    instance methods and ActionMailer tries to render a message when they
+    are called.
+
+    *Cristian Bica*
+
 *   Deprecate `*_path` helpers in email views. When used they generate
     non-working links and are not the intention of most developers. Instead
     we recommend to use `*_url` helper.
diff --git a/actionmailer/lib/action_mailer/preview.rb b/actionmailer/lib/action_mailer/preview.rb
index 33de1dc049eccebd9c5217cce224f4616c51cb03..44cf6665baea21acaa619f9d1df61cc5d1770872 100644
--- a/actionmailer/lib/action_mailer/preview.rb
+++ b/actionmailer/lib/action_mailer/preview.rb
@@ -22,7 +22,9 @@ module Previews #:nodoc:
       # :nodoc:
       mattr_accessor :preview_interceptors, instance_writer: false
       self.preview_interceptors = []
+    end
 
+    module ClassMethods
       # Register one or more Interceptors which will be called before mail is previewed.
       def register_preview_interceptors(*interceptors)
         interceptors.flatten.compact.each { |interceptor| register_preview_interceptor(interceptor) }