[Callum]

Dannii Minogue's planned X Factor comeback has been CANCELLED – after the Aussie star sensationally turned down the show's final contract offer today.

The Mirror can reveal last-ditch talks last night continued into the early hours of this morning, but today X Factor execs said they were “walking away” and looking elsewhere for a fourth judge.

A source close to the deal said: “We were really hoping to get Dannii on board but there had to be a deadline and an end to negotiations.

"We put in what we thought was a good offer, but that has been rejected so we are walking away and looking elsewhere.”

Dannii, 40, would have taken the place on the panel of Kelly Rowland who quit the show after she claimed last month she could not commit to the show.

The other three members of the panel who will take their places this year are Gary Barlow, Tulisa Contostavlos and Louis Walsh.

X Factor bosses now only have until next Wednesday, when auditions kick off in Liverpool, to try to find another judge.

A source close to Dannii, who is currently appearing on Australia's Got Talent, suggested she may have turned the show down for the sake of her son Ethan.

The friend added: “It won't have been about money for her, she obviously just decided that she didn't want to do it and that is that.

"There has been a lot going on in her life recently.”

Last month Dannii hit the headlines after a biography on Simon Cowell revealed that he had sex with her while the pair were both judges on The X Factor after she joined the show in April 2007.