Louis Walsh, Britney Spears, Demi Lovato and LA Reid in Kansas City Last week (Brian Prahl / Splash News)
Louis Walsh, probably best described as the Irish Simon Cowell, is getting a taste of what it’s like to be Cowell these days as he filled in for the sick mogul on the U.S. X Factor, alongside other judges Britney Spears, Demi Lovato and LA Reid.

Cowell took sick with a bug and recruited his buddy Walsh, who’s a judge on the U.K. X Factor.  He dispatched his private jet to London and flew Walsh straight into Kansas City where auditions were taking place.

“(Simon) greased the wheels with the U.S. bosses, telling them that Louis was the man who knew more about The X Factor than any other judge,” a source said.

Mayoman Walsh seems to have gotten along great with Spears, Cowell’s Hail Mary hire in the hopes of shoring up the show’s second season ratings.

"I loved Britney. She is such a star. She's really bright, really brilliant, she has it totally sussed,” Walsh said.