Rihanna was the belle of the ball as she stepped out in LA last night for the 2012 GQ Men Of The Year party.  See flicks of RiRi, Diddy, Cassie, Frank Ocean and more partying it up inside......

With her nude GQ magazine cover flying off magazine racks, Rihanna stepped out in a Calvin Klein red mini dress for the publication's 2012 "GQ Men Of The Year" party last night.

The big bash was held at the Chateau Marmont where the "Diamonds" singer partied it up with her celeb friends.

Oscar-winner Jamie Foxx chatted it up with the pop star.

She posed with the hilarious "Modern Family" star Eric Stonestreet. 

GQ publisher Chris Mitchell also posed with RiRi.

Frank Ocean sipped a few cocktails with the bad girl in his Yves Saint Laurent Razorblade Sweater.

Singer Cassie Ventura wore a sexy black gown with a revealing slit.  Maybe it's just the pose but looks like some double sided tape would have done wonders for this look.  Gorgeous look still.

Cassie was there with Diddy who looked very stylish in a navy blue shirt and black slacks.

"Empire Girls" star Adrienne Bailon donned a leather dress.

Actress Jessica Szohr wore a cute blouse with a little "peacock" flair and mini shorts to show off her hot gams.

Stylish rapper Common walked the black carpet in a blazer and dark trousers.

Kid Cudi flashed his pearly whites.  Great suit for him.

"Let Me Love You" singer Ne-Yo rocked a button-down shirt giving off a lil sexy.

He posed with "X Factor" judge LA Reid.

Meanwhile, Big Sean stepped out in a printed Katie Eary shirt with red Adidas Original sneakers.  This shirt is PURE comedy.  Sorry.

Stylish trio Kid Cudi, GQ senior editor Will Welch and Miami Heat baller Chris Bosh enjoyed the party atmosphere.

And Jaime Foxx had to stand on a chair to pose with Chris Bosh and he still wasn't eye-level!

Project X star Miles Teller posed with Frank and Kid Cudi.

BONUS:

Rihanna posted a special "Miss You" message to a certain someone on Twitter yesterday. While rocking a graphic t-shirt, scarf print joggers and covering her face with a vintage Chanel purse, RiRi gave off a suggestive pose. We don't know who the message is to but we would assume it's for Chris Brown. I mean, just sayin'....

Photos via Instargram/Michael Kovac/Getty Images North America