Kim Kardashian had a lot to celebrate last night in Las Vegas!

The reality TV star marked her 33rd birthday with a huge bash at Tao Nightclub at The Venetian in Sin City -- where she showed off her GIANT 15-carat engagement ring from Kanye West and her incredible post-baby bod.

Clad in a sexy white lace dress, the new mom put her killer cleavage on display. The white number also highlighted her hourglass figure and showed a hint of her stomach.

Her hair looked great too -- motherhood is clearly agreeing with Kim!

The 33 year old was joined by her fiance, sisters Khloe and Kourtney, mom Kris Jenner and Kourtney's baby daddy Scott Disick for the party.

Check out all the fun photos above -- it looks like they had a blast!

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