Britney Spears walks out during X Factor audition

Britney Spears and Demi Lovato walked out of an audition on the US version of The X Factor on Saturday after a would-be contestant refused to look at them.

The two singers serve as judges on the new series of the show, but they quit the studio alongside music moguls Antonio 'L.A.' Reid and Louis Walsh when the unnamed hopeful turned his back on them.

An onlooker at the audition in Kansas City, Missouri tells People.com, "It was really awkward. You could tell the judges were done. I don't think they had a choice. They didn't want to waste their time."

Another source adds, "(The contestant) was one of the worst singers and had a bad attitude... (The judges) all hated it and walked off."

Irish boyband boss Walsh jetted to Kansas to temporarily replace his pal Simon Cowell as a judge on the show while he recovers from a bout of bronchitis.