Britney Spears [1] and Iggy Azalea were so much more than "Pretty Girls" at the Billboard Music Awards in Las Vegas. The icon and rapper worked the stage with a vengeance [2] on Sunday, hitting all the marks with the first live performance of their new single. While the fun video for their catchy Summer jam [3] showcases the duo's shenanigans in a 1980s fantasy, their performance highlighted Britney's dance moves and her insane body — did you see that costume? Clap for Britney when you scroll through her new pictures, then watch Britney stun on the red carpet [4] with her boyfriend, Charlie Ebersol.