NICOLE'S FURY KEITH & KATY'S ON-SET FLIRTING!

It's feared the wrong sparks could soon be flying on Idol

Keith Urban can’t wait to get back on to the set of American Idol after announcing his upcoming return as a guest mentor. It’s been seven years since he flirted up a storm with fellow judge Jennifer Lopez on the hit talent show – and insiders say his wife Nicole Kidman “is bracing for more of the same” when it comes to current judge Katy Perry.

“Keith is a huge fan of Katy’s,” reveals an insider. “One of his favourite songs is Teenage Dream.

“He’s never made a fuss over performing in front of other judges, but this time, with Katy there, he’s making a huge effort to put on a perfect show. He’s always admired her vocal range and has a terabyte of songs he’d love to record with her.”

However, friends say Nicole’s not going to sit back and let her husband, 55, embarrass himself in front of his musical crush.