Kim and Rhehana shows off. (photos)

Kim K looked beautiful in a plunging sheer sequin gown, which she wore over a revealing bodice as she attended Rihanna's first-ever Annual Diamond Ball held in honour of the Clara Lionel Foundation at The Vineyard in Beverly Hills last night. Rihanna looked even more stunning in a rose satin gown. See more pics from the charity event after the cut...

This is when she was performing

 Photo credit: Getty/Access Photo