1 files changed, 6 insertions, 0 deletions
diff --git a/activemodel/lib/active_model/type/date_time.rb b/activemodel/lib/active_model/type/date_time.rb
index 5cb0077e45..9641bf45ee 100644
--- a/activemodel/lib/active_model/type/date_time.rb
+++ b/activemodel/lib/active_model/type/date_time.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   module Type
     class DateTime < Value # :nodoc:
@@ -10,6 +12,10 @@ module ActiveModel
         :datetime
       end
 
+      def serialize(value)
+        super(cast(value))
+      end
+
       private
 
         def cast_value(value)