George Clooney reached the milestone on Friday and marked his big day the evening before by dining out with Elisabetta Canalis at Chinese restaurant Mr Chow.
But his hopes of going incognito were dashed - fellow diners Kirstie Alley and Jackie Collins were looking on in awe at the Hollywood hunk.
In a series of posts on her Twitter page, Alley writes, "I'm having dinner and I swear this is the most star studded restaurant I've ever been in!!... Impressive!!!"
"I was at Mr. Chows... Best food forever in LA... Happy birthday George Clooney... Great to see u... Better to hug u."
Collins adds, "Fun dinner at CHOWS. With Kathy Griffin. Spotted George Clooney & beautiful gf (girlfriend) Elizabetta (sic)."
Alley later sent a 'Tweet' to Collins, declaring, "Great seeing u tonight... Were we surrounded by beautiful men or what?? Mr. Chows it is every nite (sic)."