American Idol is the world's most popular reality TV show. A quartet of judges grade a parade of contestants, aspiring singers from around the nation.

Ryan Seacrest hosts the show, which has crowned champions that have gone on to massive success. The leading examples are Carrie Underwood and Kelly Clarkson.

Contestants that haven't won, such as Daughtry and Clay Aiken, have also enjoyed enormous appeal and commercial success.