Katy Perry didn't hold anything back during her Grammy Awards performance on Sunday evening. A Katy Perry impostor actually kicked things off pretending to be the pop star singing "ET" before the real Katy emerged to debut her brand new single, "Part of Me." Decked out in a skintight latex suit, Katy showed off her dance moves and attitude with the breakup anthem. The track will be included on her upcoming rerelease of Teenage Dream, and while it was recorded before her divorce from Russell Brand, she did change the lyrics for the Grammys show to specifically address her own recent split. Watch Katy Perry's Grammy performance video now!