Access script from a namespace

I just came across a situation: I’d like to have access to a class i wrote, which I didn’t included in any namespace, from the script ThirdPersonUserControl (from standard assets), which is in the namespace UnityStandardAssets.Characters.ThirdPerson.

The problem is the class name is unknown, as if i was missing a “using”.
So I was wondering if there is a default namespace for the scripts created in unity, or if there is another problem in what i did, that i’m not aware of?
I didn’t find topics answering it.

There is no default namespace for the classes you define.
If you didn’t put your class in a namespace, it should be available from any other class.

Are you modifying the script ThirdPersonUserControl and want it to handle your custom class?