Justin Bieber performs with backup dancers during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Justin Bieber performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Ke$ha performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Justin Bieber performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Ke$ha performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Justin Bieber performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Flo Rida wades into the audience during his performance on the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Psy, center, performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Pitbull makes a guest appearance during Afrojack's set on the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Pop star Justin Bieber performs during the second night of KIIS-FM's "Jingle Ball" at the Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Chris Pizzello/Invision/AP)
Ke$ha performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Adam Young of Owl City performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Afrojack, left, is joined by guest performer Pitbull during his set on the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Psy, center, performs with backup dancers during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Ryan Seacrest, left, and singer Alicia Keys introduce Justin Bieber during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Justin Bieber performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Psy, center, performs during the second night of KIIS FM's Jingle Ball at Nokia Theatre LA Live on Monday, Dec. 3, 2012, in Los Angeles. (Photo by Chris Pizzello/Invision/AP)
Singer Anya Marina performs during the Twilight Fan Camp Concert outside Nokia Theater L.A. Live, Saturday, Nov. 10. 2012, in Los Angeles. The world premiere of the film "The Twilight Saga: Breaking Dawn Part 2" will be held at Nokia Theater L.A. Live on Monday. (Photo by Chris Pizzello/Invision/AP)
Singer Christina Perri performs during the Twilight Fan Camp Concert outside Nokia Theater L.A. Live, Saturday, Nov. 10. 2012, in Los Angeles. The world premiere of the film "The Twilight Saga: Breaking Dawn Part 2" will be held at Nokia Theater L.A. Live on Monday. (Photo by Chris Pizzello/Invision/AP)