Video: Rihanna, Christina Aguilera's Live Performances on 'X Factor' Finale

Rihanna and Christina Aguilera visited "The X Factor" finale with a bang over the weekend. RiRi was joined by Matt Cardle in a live "Unfaithful" duet, later telling him that he was "going to go far." Aguilera collaborated with Rebecca Ferguson for "Beautiful", praising her as "a very unique talent." The other musical guests were will.i.am and Robbie Williams. The Black Eyed Peas member shared