Here are some famous birthday wishes for Mr. Nasty...
One Direction's Zayn Malik (@zaynmalik) calls him Uncle?! Awww!
Also a big Happy Birthday to Uncle Si @SimonCowell
His favorite stateside brat, Demi Lovato (@ddlovato), gets in a good dig:
Today is a great day....it's @SimonCowell's birthday which means he's even OLDER now!!! #HappyBirthdaySimon
Britney Spears (@britneyspears) takes the sweet route:
Happy Birthday @SimonCowell!!!! Make sure you all tweet him some birthday wishes xxoo #HappyBirthdaySimon
Toni Braxton (@tonibraxton) sends her love:
Happy Birthday @SimonCowell ! Wishing you many more :)
Gossip guru Perez Hilton keeps it simple:
@SimonCowell Happy birthday, Simon!!!
Ellen DeGeneres' favorite little lady Sophia Grace (@PrincessSGB) gets in on the action:
Happy Birthday @SimonCowell, Love from Sophia Grace Xxx
Season 1 cutie Drew Ryniewicz (@drewryniewicz) didn't forget her former mentor:
Happy Birthday!! @SimonCowell
What would YOU get Simon for his birthday? Hit the comments below and let us know.
Tune in THE X FACTOR on WEDNESDAY and THURSDAY at 8/7c on FOX for the final showdown at Boot Camp when 60 become 24 and then it's onto Judges' Homes.