Alex & Sierra left a mark with their performance of A Great Big World's "Say Something." What did their mentor, Simon Cowell, have to "say" afterwards? "Say Something" performed by "Alex and Sierra" on THE X FACTOR USA. Buy now on iTunes: http://bit.ly/1cYRTbF Subscribe now for more THE X FACTOR USA clips: http://bit.ly/TXF3_Subscribe Tune in to THE X FACTOR USA Wednesday & Thursday 8/7c on Fox! Like THE X FACTOR on Facebook: http://bit.ly/TheXFactorUSA_FB Follow THE X FACTOR on Twitter: http://bit.ly/TheXFactorUSA_Twitter Add THE X FACTOR on Pinterest: http://bitly.com/TXF_Pinterest Add THE X FACTOR on Google+: http://bit.ly/TheXFactor_GooglePlus See more of THE X FACTOR on our official site: http://www.thexfactorusa.com/ Like FOX on Facebook: http://fox.tv/FOXTV_FB Follow FOX on Twitter: http://fox.tv/FOXTV_Twitter Add FOX on Google+: http://fox.tv/FOXPlus The award-winning international phenomenon THE X FACTOR is back. In Season Three of the hit competition series hosted by Mario Lopez, THE X FACTOR judges will travel the nation searching for talent 12 years old or over -- both solo artists and vocal groups -- who are willing to brave the panel for a chance to make their dreams of becoming a superstar come true. Auditions for THE X FACTOR were held this spring in Los Angeles, CA; Charleston, SC; New Orleans, LA; Long Island, NY; and Denver, CO. Contestants will audition in front of THE X FACTOR judges, including Simon Cowell, Demi Lovato, Kelly Rowland, Paulina Rubio, and an audience of thousands. This will be the ultimate test to prove they have the vocal ability, charisma and stage presence it takes to become a global superstar or breakout music act and win a recording contract with Syco/Sony Music. Those contestants who survive the first auditions will be divided into four categories: Boys, Girls, Over 25s and Groups. Each category will be mentored by one of the show's judges. Not only is it a competition between the hopefuls to stake their claim for the coveted win, but it's also a showdown among the judges as to whose acts will dominate the competition and make it to the finals. The judges may have their say in how the competition progresses, but it will be up to America to decide who ultimately has THE X FACTOR. Alex & Sierra's "Great Big" Performance! - THE X FACTOR USA 2013 http://www.youtube.com/user/TheXFactorUSA