Looking good, Kylie Jenner.

The 18-year-old showed off her curvaceous figure at Rihanna's Diamond Ball on Thursday — and she rocked an outfit that would give Kim Kardashian (and her butt) a run for her money!

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kylie jenner

Kylie kept her long, dark hair in loose waves and her makeup light.

We bet her 26-year-old boyfriend, Tyga, was pleased with the look!

RELATED: Kylie Jenner Receives Backlash After This Controversial Photo Shoot

Scroll through to see more of the famous family members' ass-ets.