Whom was Kilmer ... *spoiler*

... impersonating?

I thought that was a really funny break in the movie, which, after all, wasn't that scary; although it was sad that after the montage of impersonations when Hall is trying to start his book, we then learn he lost his daughter. That was hard to take.

But before that, I was pretty much rolling when Kilmer was doing the two famous guys and the basketball player who turned out to be gay. I got the first impersonation, Brando. The second one was really familiar, but I just couldn't place him. Who was it?