The winner of season 4 will return to the Ryan Seacrest-hosted show on this year's finale, joining Christina Aguilera.
Carrie Underwood has been hired to make a live performance at the next week episode of "American Idol". The winner of the show's fourth season will return to the "Idol" stage to deliver her single "Undo It".
Joining her to perform on May 26 before host Ryan Seacrest announces the winner of season 9 is Christina Aguilera. The 29-year-old singer comes to the singing competition in an effort to promote her June 8 release "Bionic" and she will perform one of her new songs "Not Myself Tonight".
"American Idol" itself has booted Casey James this week, leaving two remaining contestants, Crystal Bowersox and Lee DeWyze. They are going to face off against one another on May 25 with three performances. The first round is the contestant's choice, the second is producer Simon Fuller's choice and the third one is the winner's single.