I think so long as it's just a reference it's all fair game. I can't see a show like South Park having to pay every time they mention a celebrity (or even have them as characters on their show, voiced by others).

If you were trying to make a biopic, that might be different...

Morgneto, Master of Morgnetism

It depends on what you want to do with their name..
If it's for Films Independent..
It's fine
But if you want to do in festival,,
You probably have to read the license about it

Nada Taufik
Film Maker
pink_rebels?filmsindie.com
http://www.filmsindie.com/pinkrebels