Dermot announced his decision to leave the ITV talent show this afternoon, saying it's "time to move on".
He said in a series of tweets: "After eight wonderful years on @TheXFactor it's time for me to move on. I'd like to thank ITV, Simon, The X Factor family and particularly the viewers, all of whom have been a big part of my life for so long.
"I'd like to wish the team all the best for the future, especially whoever takes over from me."
Giving advice to his predecessor, he added: "You're about to be the conductor on the most brilliant, runaway train in showbiz. Good luck you'll love it."
Dermot has been presenting the ITV talent show for eight years after taking over from Kate Thornton in 2007.
In January, Dermot revealed he would love Emma Willis to take over from him on the ITV talent show.
Just a week before, Dermot admitted he was unsure if would present the next series of The X Factor.
"I haven't made up my mind yet," Dermot told Radio Times magazine at the time. "I love doing [X Factor] and it's a huge part of my life. But it's eight years now."
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