For example, Diana Ross told David Letterman that she is going to be on the show later this season. She won't be a judge, as Jewel served as last night. Instead, the icon will help prepare contestants for future performances.
During a taping of The Late Show yesterday afternoon, the legendary singer told Dave:
"I'm going to do the American Idol, as a mentor. And then I'll leave from there and I'll go on tour, March and April."