Rihanna performs her biggest hits at ‘Diamond Ball’...

Before listing Rihanna’s many accomplishments (54 million albums sold, and seven Grammys won), Brad Pitt sure had fun introducing Rihanna’s performance last night.

During her inaugural Diamond Ball charity gala in Beverly Hills, Rihanna stepped onto the stage in a gorgeous dark blue Zac Posen gown and huge Chopard diamond necklace and sang a medley of her hits with a live orchestra.

Rihanna's 'Diamond Ball' raised a super cool $4 million last night for cancer. Watch all the performances and action unfold below! 

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