alums Ruben Studdard and Clay Aiken on Sunday night. The season 2 winner and runner-up, respectively, returned to the stage 20 years later for the season 21 finale, performing a duet to «The Impossible Dream,» with the help of season 21 winner and runner-up Iam Tongi and Megan Danielle.«It was really good, man. You know, I just definitely enjoyed myself,» Studdard told ET's Denny Directo after the performance.