The 41-year-old singer – who is due to give birth to twins in the coming weeks, her first children with husband Nick Cannon – will have a role on the new pop star search show, according to series boss Simon Cowell, but he won’t reveal what it is.

In a radio interview with Jackie Brown, he said: “I think Mariah will have a role on the TV live shows. I met her recently and she was on great form. And her idea was to be the judge of the judges, which only Mariah could come up with.”

Simon is excited about having Mariah involved with ‘The X Factor’ because he is such a big fan of her music.

He added: “She'll be involved in some form. I literally adore her. I love her to bits."

Speculation about who is joining Simon on the judging panel has been rife.

So far, only the 51-year-old music mogul and record executive L.A. Reid – who is the former Chairman of Island Def Jam Music Group – have been confirmed.

Among the numerous stars to be linked to judging spots are Cheryl Cole – who appears on the UK version of the programme - Nicole Scherzinger, Jessica Simpson and Katy Perry.

R’n’B superstar Rihanna turned down an offer to be a judge because she cannot appear when it launches this autumn on Fox later this year due to her touring commitments.

She said: "It's something that I would have loved to do, actually. But our schedule doesn't allow it and it's a demanding schedule to be on that show.

"You have to be around months at a time, which is impossible for me."