diff --git a/lib/validates_timeliness/orm/active_record.rb b/lib/validates_timeliness/orm/active_record.rb
index 9fda881..3a7c568 100644
--- a/lib/validates_timeliness/orm/active_record.rb
+++ b/lib/validates_timeliness/orm/active_record.rb
@@ -11,7 +11,7 @@ module ValidatesTimeliness
   end
 end
 
-class ActiveRecord::Base
+ActiveSupport.on_load(:active_record) do
   include ValidatesTimeliness::AttributeMethods
   include ValidatesTimeliness::ORM::ActiveRecord
 end