Demi Lovatomay seem like a sweetheart to most people, but the 20-year-old X Factor judge does have a major sassy side! Demi and fellow judge Simon Cowell paid a visit to Conan O'Brien's late night show to promote the second season of X Factor and the duo both unleashed their cat claws! While talking to Conan, Simon called Demi, "annoying." Demi's response? She calls Simon an "a**hole"... to his face! OMG! Check it out in the video below and let us know what you think!
Who do you think is the "meaner" judge on X Factor: Demi or Simon?