Walsh, who filled in for a sick Simon Cowell at the Kansas auditions, was not known by the other three US judges.
"I think this guy called Louis is going to be here," comments Spears.
A shocked Reid asks: "Who the hell is Louis?"
In a VT about his career, Walsh brags about selling millions of records around the world and adds: "When Simon needs an opinion from someone he trusts, I'm the man he calls."
> X Factor USA third auditions episode - recap
Walsh attempts to get on side with his co-stars by joking about becoming a permanent replacement for Cowell.
"Britney, we might not want [Simon] back!" he shouts.
X Factor USA continues tonight (September 20) on Fox. It will air in the UK on ITV2 later this month.
X Factor USA latest pictures:
Copyright: Fox Ray Mickshaw