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

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

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Keith Urban can't wait to get back onto 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 - one of his favourite songs is Teenage Dream," reveals an insider.

"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.

"She's told Keith to keep his distance," adds the insider.

"She doesn't want another rehash of rumours like last time with J.Lo, but it's also fair to say Nicole's always been insecure about someone so musically talented as Katy.

"Nicole's a master in her craft, but completely out of her depth when it comes to connecting to Keith's musical passions.

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