diff --git a/activesupport/lib/active_support/core_ext/date_time.rb b/activesupport/lib/active_support/core_ext/date_time.rb
index 67463d2352..dc5dceaea5 100644
--- a/activesupport/lib/active_support/core_ext/date_time.rb
+++ b/activesupport/lib/active_support/core_ext/date_time.rb
@@ -1,5 +1,4 @@
+require 'date'
 require "#{File.dirname(__FILE__)}/time/behavior"
 
-class DateTime
-  include ActiveSupport::CoreExtensions::Time::Behavior
-end
\ No newline at end of file
+DateTime.send(:include, ActiveSupport::CoreExtensions::Time::Behavior)