Singers Mariah Carey and George Michael, former Pussycat Doll Nicole Scherzinger and ex-"American Idol" judge Paula Abdul are all in the running to join Simon Cowell on his upcoming talent show "The X Factor," Cowell said on Thursday.

But none of them are locked in as judges for the upcoming TV show, and Cowell told celebrity TV show Access Hollywood he was in no hurry to make a decision.

Singer Jessica Simpson was also reported this week to be keen for a spot on the panel of the singing contest. But sources close to the show told People magazine that a final decision may take weeks.

Cowell told Access Hollywood he had spoken to Carey, who is pregnant with twins.

But he added; "We've spoken to lots of people. I've spoken to Paula...we've taken it down to a smaller group of people and she (Abdul) is in that panel. But you know, it's more than me who makes the decision."

Despite their often tempestuous relationship on "American Idol", Cowell has made no secret of his admiration and off-set friendship with the volatile Abdul.

Cowell said last month that he would be one of the "X Factor" judges.

The U.S. version of the "The X Factor" is due to debut on Fox in the fall of 2011, offering an unprecedented $5 million prize for the winner, along with a record contract.

But unlike "Idol", the "X Factor" judges will mentor the contestants closely, helping them with song choice, production, coaching and even style during the TV contest.

"It's good to kind of delay the process...You genuinely have got to trust they they're going to be able to do the job you're paying them to do," Cowell said of the new panel.

Cowell said that singers Katy Perry and Elton John -- whose names were floated in the media earlier this year --are not on the short list.