X-Factor Judges Walk Off

Sources at the taping in Kansas City tell TMZ ... Britney, Demi, L.A. Reid and Simon Cowell's stand-in, Louis Walsh, couldn't stomach one more second of a certain wannabe superstar's "singing" and were so disgusted by it ... they walked out mid-audition.

We're told it all went down because the guy auditioning walked on stage and then turned his back to the judges to sing with his eyes closed. After a few bars of melodic torture, the audience started booing and the judges peaced out.