The Hangover star Ken Jeong made a hilarious appearance on Kelly Clarkson's holiday Tv special, Kelly Clarkson's Cautionary Christmas Music Tale, as her manager. The Since U Been Gone hitmaker was also joined by Robin Williams, Whoopi Goldberg, William Shatner, Heidi Klum, and Blake Shelton for skits and songs, and teamed up with Trisha Yearwood and Reba MCEntire to perform Silent Night on the show, which aired in the U.S. on Wednesday (11Dec13).