Thriller

Well I'm pretty much doing nothing so I was on the computer and saw on msn video "darth vader doing thriller", and well it was weird. I decided to watch the real "Thriller", and I now have a new definition of weird. I just have one question though, how did michael jackson get his voice to be that high pitched, I mean did he go through some sort of surgery on his voice or did he accidently breath a lot of helium when he was little?