Irish export Louis Walsh stepped into Simon Cowell’s role on US X Factor this week, to the surprise of his fellow judges.

According to reps, Cowell was struck down with bronchitis and called in Irish pal Louis to fill his shoes for the Kansas auditions.

In a staged interview at the start of the episode, Britney Spears broke the news to her fellow judges that Cowell would be absent: “I think this guy called Louis is going to be here."

No stranger to the X Factor, Walsh has appeared as a judge on the UK version of the show on-and-off since 2004.

Not familiar with Walsh’s work, judge L.A. Reid asked Spears: “Who the hell is Louis?”

In short video introduction, Walsh bragged about selling millions of records around the world.

“I have managed some of the biggest boy bands in the UK and Ireland.”

Walsh added: "When Simon needs an opinion from someone he trusts, I'm the man he calls."

The 60-year-old Mayo man wore a black suit and pink button-up shirt and seemed perfectly comfortable alongside fellow X Factor judges, L.A. Reid, Demi Lovato and Britney Spears.

Despite his cameo on US X Factor, the Irish man insists the UK X Factor has still got the edge.

"The people that show up are incredible. The shows deliver pop stars like Olly Murs, One Direction, Alexandra Burke, Leona Lewis... it's not necessarily the people who win the shows that are successful,” Walsh said.