diff --git a/lib/ex_twilio/resources/message.ex b/lib/ex_twilio/resources/message.ex
index ef5191f..2f52b53 100644
--- a/lib/ex_twilio/resources/message.ex
+++ b/lib/ex_twilio/resources/message.ex
@@ -33,7 +33,9 @@ defmodule ExTwilio.Message do
             api_version: nil,
             uri: nil,
             subresource_uri: nil,
-            messaging_service_sid: nil
+            messaging_service_sid: nil,
+            content_variables: nil,
+            content_sid: nil
 
   use ExTwilio.Resource,
     import: [