Brown picked up three awards, and he thought he had landed the Coca-Cola Viewer's Choice Award too when a fan, who won a competition to hand out a prize at the show, read out his name.
However, the girl reportedly suffered a teleprompter mishap and backtracked, saying the award was really destined for Rihanna - so rapper Drake took the stage to pick up the prize on her behalf.
Rihanna even sent out a message to fans via Twitter.com thanking them for the award, writing, "Thank you for proving what I tell the world everyday! Nobody fans go hardr (sic) dan (than) y'all!!! Thx (sic) 4 pickin (sic) that up Drake".
However, the mistake was realized later in the show when host Kevin Hart revealed Brown had won the Viewer's Choice Award after all, according to Entertainment Tonight.
Brown also won best Male R&B Artist, best Collaboration for Look At Me Now with Lil Wayne and Video of the Year, while Rihanna scooped best Female R&B artist.