This month the first confirmed details about 2018's series were revealed, with auditions heading back to arenas.
But as yet the judges have still to be announced.
Rita - who was a judge in 2015 - is the current firm favourite to become the fourth member of the X Factor panel, when the show returns later this year.
Head judge Simon Cowell is returning, and he is expected to confirm that Louis Walsh and Sharon Osbourne will again be in board, but there will be space for at least one new judge after it was reported Nicole Scherzinger would not be back.
Cheryl was widely expected to return for her third stint on the show, but after it was revealed she was taking part in new BBC show The Greatest Dancer – her odds have drifted.
Now another former judge is firm favourite, in the shape of Rita Ora – who won with Louisa Johnson during her last stint.
Rita is said to be the frontrunner ahead of Mel B, who reportedly faces legal issues related to ex-husband and daughter in America.
“Mel would really like to return home to the UK for a spot on The X Factor," a source told the Daily Star. “The chemistry with Simon on the new series of America’s Got Talent is really strong, so bringing her back is an option.
“But the legal issues that she faces over her daughter Madison are tough.”
“Rita Ora is firm favourite for the fourth seat,” said OddsMonkey spokesman Peter Watton. “She is around 4/9 to return which is a near 70% probability ahead of Alesha Dixon – who is already judging next to Simon on Britain’s Got Talent – at 11/4.
“Two other who have seen their odds cut in recent weeks have been the Little Mix girls, Jesy, Perrie, Jade and Leigh-Anne – whose odds are all around 14/1 – having been twice that just a few weeks ago.”
The X Factor 2018 will air on ITV in the autumn.