Shock! Chris Brown didn't beat up Rihanna at her party

Feb 16, 2012 at 7:17 p.m. ET

Chris Brown and Rihanna cozied up at the "Umbrella" singer's birthday party Monday night -- and he managed not to give anyone a beat down the whole night.

Rihanna and Chris BrownGuess who was the very special guest at Rihanna's intimate birthday party Monday night? If you guessed the guy who beat the crap out of her just three years ago, you win the golden boxing glove!

Despite denying rumors that they're back together, Rihanna and Chris Brown definitely looked like a cozy couple at the party, witnesses said.

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Despite Brown trying to get all the guests to sign a non-disclosure agreement before he entered, one guest spilled the beans on Twitter -- and the news is rather disheartening to those of us who want to see Rihanna put the whole episode behind her.

"If Cupid was here he would be very happy everyone @Rihanna bday party was coupled up," said partygoer "Katia C" on Twitter.

"All I can say, CB was invited and she [Rihanna] was acting like the happiest girl on her birthday and probably got what she asked for."

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Bruno Mars, Kelly Rowland and Chris Martin were all at the bash -- and so was Rihanna's BFF Katy Perry, whose antics got tongues wagging.

"Rihanna and Katy had everyone going crazy. By the end of the night they started a cake fight and were dancing together while Bruno and Chris looked on open-mouthed, cheering," a source told The Mirror.

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"At one point Katy danced so much she broke her heels and had to leave the party barefoot. Rihanna also had her own wardrobe casualty when her corset came undone but she didn't let that stop the fun."

Rihanna's super classy birthday cake featured an icing drawing of the topless singer riding a giant spliff like a race horse.

Image courtesy WENN