Katy Perry
Katy Perry performed her latest single 'Firework' live on the 'X Factor' results show wearing a sparkling black catsuit while pyrotechnics lit up the stage. The crowd cheered the singer on, but Perry's nerves may have gotten the best of her. After several blogs complained that she sounded flat, she took to her Twitter page to tell fans how nervous she was about performing. "I was so nervous! Thanks 'X-Factor' for making me feel like I was actually one of the contestants." Watch: