Jennifer Lopez premiered her new single 'Louboutins' at this year's American Music Awards but, unfortunately for J. Lo, the performance did not go without a hitch. The singer fell flat on her butt in the middle of her comeback performance when she took a break from busting a move and climbed on the backs of her dancers who formed a makeshift set of steps. The pop diva jumped from the top of the human ladder but failed to land securely on her feet. Instead, the 40-year-old singer/actress landed on her famous bottom.