American Idol is in the midst of its 18th season, looking for the latest aspiring singer to join its long history of superstars that have gained successful careers from the competition since it launched in 2002.Throughout the show's 18-year history, viewers have seen singers from all genres and of all ages take the crown--and also a mix of celebrity judges helping the contestants through the competition, starting with OGs Simon Cowell, Randy Jackson and Paula Abdul leading all the way up to the