The X Factor 'The X Factor' crowns Alex & Sierra duo the champions of third season 12/20/2013 Alex & Sierra were named The X Factor's third-season winners during the Fox reality singing competition's live finale on Thursday night. Read More RELATED NEWS 'The X Factor' alum Jeff Gutt has "zero trepidation" about first tour as Stone Temple Pilots front-manDemi Lovato on her troubled past: "I didn't think I would make it to 21"Demi lovato discusses sobriety and her jealousy of Miley Cyrus TAGS: The X Factor Simon Cowell Jeff Gutt Mario Lopez Kelly Rowland Paulina Rubio Mary J. Blige Leona Lewis Pitbull Carlito Olivero
