Carrie Underwood will return to American Idol for the season finale on Wednesday (May 26). She will perform "Undo It" during the episode. Underwood, who won the American Idol competition in 2005, sang on the Fox series earlier this year during the "Idol Gives Back" special. Her upcoming dates on her Play On tour include Thursday (May 20) in Sacramento, Calif., Friday (May 21) in Reno, Nev., and Saturday (May 22) in Las Vegas.