Shining Bright: Rihanna Wows In Billowing Black Bouffant Gown

As Rihanna hosted her inaugural Diamond Ball on Thursday, she pulled out all the stops to ensure that it would be a memorable affair. And the Grammy-winning singer, 26, also wowed in the style department, as she stepped out in two stunning Zac Posen gowns for the glitzy charity gala, held at The Vineyard in Beverly Hills, California.