[Press Release - Released by Fox] Katy Perry and Avril Lavigne will join AMERICAN IDOL as guest judges during the final two days of auditions held this week in Los Angeles. On their respective days, Perry and Lavigne will sit at the judges’ table next to Simon Cowell, Randy Jackson and Kara DioGuardi while the final group of singing hopefuls tries for a “Golden Ticket” to Hollywood. Recently, Victoria Beckham served as a guest judge in Denver and Boston, Mary J. Blige shared her expertise in