Diana Ross to Serve as American Idol Mentor

American Idol kicked off his sixth season last night. We've got every detail covered between now and the May finale.

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."