MC Hammer performs during “Gangnam Style” at the 40th Anniversary American Music Awards in Los Angeles. (Photo by John Shearer/Invision/AP)

PSY performs “Gangnam Style” at the 40th Anniversary American Music Awards in Los Angeles. (Photo by Matt Sayles/Invision/AP)

Carly Rae Jepsen performs at the 40th Annual American Music Awards in Los Angeles. (Photo by Matt Sayles/Invision/AP)

Usher performs at the 40th Annual American Music Awards in Los Angeles. (Photo by Matt Sayles/Invision/AP)

Gwen Stefani and No Doubt perform “Looking Hot” at the 40th Annual American Music Awards in Los Angeles. (Photo by Matt Sayles/Invision/AP)

Kelly Clarkson performs a medley of her songs at the 40th Annual American Music Awards in Los Angeles.(Photo by Matt Sayles/Invision/AP)

Christina Aguilera performs “Lotus”, “Army of Me” and “Let There Be Love” at the 40th Anniversary American Music Awards in Los Angeles. (Photo by John Shearer/Invision/AP)

Carrie Underwood performs “Two Black Cadillacs” at the 40th Anniversary American Music Awards in Los Angeles. (Photo by Matt Sayles/Invision/AP)

Ludacris performs “Everyday Birthday” at the 40th Anniversary American Music Awards in Los Angeles. (Photo by Matt Sayles/Invision/AP)

Chris Brown performs “Everyday Birthday” at the 40th Anniversary American Music Awards in Los Angeles. (Photo by John Shearer/Invision/AP)

Stevie Wonder and the Rickey Minor Band perform “Master Blaster”, “My Cherie Amour” and “Sir Duke” during a tribute to Dick Clark at the 40th Anniversary American Music Awards in Los Angeles. (Photo by John Shearer/Invision/AP)