What, you thought Britney Spears was the only one feeling feline last night? Heck, she wasn't even the only cat at the Green Door - as you can certainly see, hostess Heidi Klum was rockin' a for-real catsuit too! The supermodel showed up to her own "Heidi's Halloween" party wearing a super-sexy kitty outfit - complete with a tag on her collar reading "If found, please return to Seal"!

Of course, since Heidi's big bash was all for charity - specifically the Surfrider Foundation - plenty of other celebs turned up to show their support; we spotted Nicky Hilton, David Katzenberg, and Kyle Maclachlan in attendance. And, of course, a few other familiar faces stopped by as well!