Simon Cowell is eyeing up Katy Perry to join the US X Factor judging panel.

The music mogul is looking for stars to replace Paula Abdul and Nicole Scherzinger and Katy has already appeared as a guest judge on the UK X Factor.

Simon told his ex-girlfriend Terri Seymour in an interview for US show Extra: “I worked with Katy once. I think she would be fun because she is hard – in a good way – and she’s feisty.”

He also revealed he would love Madonna on the show, despite her being ‘expensive’.

Simon said: “She would be great, in terms of experience, success… brilliant.”

He added: “I don’t think Mariah [Carey] would make that commitment. She’s just had kids.”

And Simon ruled out Sir Elton John, saying: “Absolutely not. He wouldn’t do it and he’d be really difficult to work with.”

Meanwhile, former X Factor contestants JLS are plotting for Oritse Williams to join the UK judging panel. Simon has previously said he is yet to make a decision on the line-up for this year’s show.

Bandmate JB Gill told The Metro: “I think they should make Oritse an X Factor judge, because Oritse’s a founding member of JLS.

“He knows what it takes to put together a group and to find the right components and he’s just really, really enthusiastic. He’d be fantastic.”