Kim, 33, was pictured arriving at the event in New York with younger sis Kendall and she led the way in a plunging blue and green corset gown.
The frock, designed by Ulyana Sergeenko, flashed some serious cleavage AND leg thanks to the super-low neckline and super-high spilt, and she teamed it with gold sandals and matching clutch.
Khloe, who was celebrating her 30th birthday, still looked pretty hot however, after dressing from head-to-toe in a white long-sleeved dress.
Like Kim's, the US star's floor-length number also had a thigh-high split and she teamed it with some delicate gold heeled sandals too.
Khloe's bash was held on a yacht on the River Hudson, as Khloe is currently filming Kourtney and Khloe Take The Hamptons alongside her eldest sister Kourtney in New York.
But while the girls were dressed up to the nines for the do, Khloe's boyfriend French Montana instead played it cool in a snake-print T-shirt, grey trousers and some trademark bling around his neck.
It seems the entire clan were out in force to celebrate Khloe's 30th and their presence in New York definitely got a certain two British reality stars excited!
Made In Chelsea's Lucy Watson and Riley Uggla were pretty chuffed to catch sight of Kendall, Kylie and Kris Jenner while out and about the following day!
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