Christina Aguilera and Lady Gaga Perform on The Voice, Effectively Putting ...

E! OnlineChristina Aguilera and Lady Gaga Perform on The Voice, Effectively Putting ...E! OnlineWhat a way to end the year! To celebrate the season finale of The Voice, Christina Aguilera and Lady Gaga performed together for the very first time on Tuesday, Dec. 17, in Universal City, Calif. The long-rumored rivals showed no signs of animosity as ...