The news comes hours after ITV announced that the judge and executive producer would return to the U.K. version of the singing competition series.
"I've had a fantastic time over the last 12 years, both on The X Factor and American Idol," Cowell said in a statement. "And apart from being lucky enough to find some amazing talent on the shows, I have always had an incredible welcome from the American public (most of the time!). Last year, for a number of reasons, I had to make a decision to return to the U.K. version of The X Factor in 2014. So for now, I'm back to the U.K. and I want to thank Fox for being an incredible partner and I also want to thank everybody who has supported my shows. America, I'll see you soon!"
Fox's Chairman of Entertainment Kevin Reilly said: "To all of us at Fox, Simon is more than one of the most prolific TV personalities of our time -- he's part of our family. A consummate showman and partner, there's no one more passionate or creative than Simon, and we feel so fortunate to have enjoyed such a wonderful, collaborative relationship with him over the past 12 years. Unfortunately, there is no X Factor USA without Simon Cowell, but we understand and support his decision to focus on the international formats and on the next phase of his personal life. We wish him the very best, and it's our sincere hope that we work together again soon."
Previosuly, Cowell said he was optimistic that he would return to the Fox series, despite the previous season's low ratings. Many of the judges have come and gone over the show's three seasons. Paula Abdul and Nicole Scherzinger (who, in turn, replaced Cheryl Cole) left after Season 1. L.A. Reid and Britney Spears followed suit after Season 2, and they were replaced by Kelly Rowland and Paulina Rubio.
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