The sisters sizzled on the red carpet of the bash wearing matching topknot hairstyles and floor-length dresses.
They both chose to show off their toned legs with thigh-high splits, but there was no doubt Kylie’s sequined, silver number was the more racy of the two.
The 19-year-old gave an eye-popping display, with a plunging cleavage, and the transparent patch of fabric on her hip bone, suggests the teen wasn’t wearing any underwear.
Inside the event the Keeping Up With the Kardashians stars ate pizza and posed for pictures, in which Kylie showed off a large scar on her leg.
She previously revealed it was the result of a game of hide and seek she played when she was 5 years old.
The siblings appeared to be enjoying their night out together, and Kylie took time out from partying to post a picture of her and Kendall, 21, on Instagram, captioning the snap: “Sister Date.”
For access to all our exclusive celebrity videos and interviews – Subscribe on YouTube!