I remember reading somewhere that he learned his style just for his first movie. And it was supposed to be some ancient deadly style that gave birth to Muay Thai, but I don't really remember it all. I don't remember reading about him competing.
As far as i know he has training in several styles, to what extent i don't know, but he has to have a decent level of training to do the things he does, the average guy off the street cant pretend to fight/do moves like that.