SharePoint Fill In Values

Hi

I have a category field where the end user can select the category. I need to have an option where the use can fill in their own choice, however, I still need it to be labeled other - "users fill in choice".

What is the best way to do this? I have selected to allow fill ins and have the check boxes so the user sees a blank checkbox. The only thing i need is an other in front of it.

THanks