Ignoring the oldest rule in the fashion book (reveal boobs, pins or tummy, darlings!) RiRi went for a risqué frock designed by fellow party-goer Tom Ford.
From the designer's spring 2015 collection, the backless, thigh-split number featured metallic pink embellishment and cut-out detailing aplenty.
But paired with a zingy coral lip and a sleek 'n' chic ponytail, Rihanna totally pulled it off. Check out her on-trend ear cuffs, too!
The star-studded bash, in celebration of the amfAR AIDS Research charity, featured an auction where Rihanna reportedly splashed over $100,000 on photographs and diamond jewellery.
Rihanna's no stranger to supporting AIDS charities - she has her own MAC make-up range, VIVA GLAM Rihanna, which helps men, women and children affected by AIDS and HIV around the world.
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