When I think of genre change, I think of the actor Daniel Radcliffe. Daniel was a kid star early on in his life, being recognized for his role as Harry Potter in, well, Harry Potter. After his kid career, he strove away from being a cherished kid star to a more action packed and thrill seeking character. There are many movies with him as an adult that are drastically different than anyone who has seen the Harry Potter movies and could tell. I think he was successful in pulling this genre change off as he really, really wanted to get away from his Harry Potter role and find something new, which gave him passion.
I too enjoyed his prescience in the Harry potter films, and in productions hes in now really shows his range of an actor.