Don't be fooled by the rocks that she's got -- that ain't Jenny from the Block! It's Nicole Richie!
Nicole showed off her Jennifer Lopez costume this weekend on Twitter, where she struck a very J.Lo pose while wearing a sweatsuit and sexy heels.
Of course Ms. Richie wasn't the only one dressing up over the weekend -- check out some brand new shots of Gwen Stefani as Cinderella, Matthew Morrison as Roger Rabbit, Snooki as a sexy leopard, and see what "Real Housewives of Beverly Hills" stars Camille Grammer and Kyle Richards dressed as!
We'll keep updating the gallery as new photos come in.