RIHANNA CELEBRATES HER B-DAY

Rihanna celebrated her 20th birthday with a bash this week – and cupcake fight – at Les Deux in Hollywood.

"There was frosting all over Rihanna's face and the group was hysterically laughing to the point of almost tears," a guest reports. When partygoers including Kanye West and Wilmer Valderrama weren't flinging cupcakes, they offered a standing ovation after Chris Brown sang an a capella version of "Happy Birthday."

While Brown has denied that he and the birthday gal are dating, a party guest reports the two were cuddling and acting "very cozy all night."