ITV confirmed this week that alongside Simon Cowell, three new judges will join this year's series while Sharon Osbourne will act as a fifth judge for the live shows.
Both Nicole Scherzinger and Louis Walsh have quit the series, the channel confirmed.
Louis said: “I’ve had a fantastic 13 years on The X Factor but the show needs a change and I’m ready to leave.
“I’m looking forward to another series of Ireland’s Got Talent, going back to my day job as a manager, writing my memoirs and seeing the world!”
According to the Daily Mirror, Louis is set to spill all about his time on the show in a new book.
The tabloid claims that Louis will talk about Simon Cowell and Dannii Minogue, Cheryl Cole plus all the backstage rows and gossip.
A source said: "He is going to settle a few scores."
Meanwhile, Sinitta has predicted that Louis Walsh may well end up returning to The X Factor after quitting for a third time.
"Do you think he really has? How many times has Louis quit X Factor? He says it every year. Do you think it really is it for him?" she said of news of Louis leaving.
Sinitta told the Mirror: "He's said it before and he's always gone back. It could be just a plot.
"But saying that, maybe it is time he gave up and made way for someone new. I would miss him and I think viewers will."
"Louis is a genuinely nice guy. Him and Simon are such good friends and if he really has left I'm sure they will still hang out," she added.
As yet, ITV have not confirmed who will be joining the show in place of Louis and Nicole.
Names rumoured include Robbie Williams, former The Voice UK coach Kylie Minogue and One Direction's Louis Tomlinson.
The X Factor 2018 will air on ITV later this year.