Simon Cowell had been the mainstay judge on  Fox's "The X Factor," which had a revolving door of other personalities.

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Simon Cowell announces he's leaving "The X Factor"

Fox cancels "The X Factor" after three seasons

The reality show judge is returning to "The X Factor" in the UK

CNN  — 

Reality singing competition “The X Factor” has lost its flagship star and its place on Fox’s lineup.

On Friday, judge Simon Cowell announced he was leaving the American version of “The X Factor” to return to the original UK iteration, news that came as Fox confirmed “The X Factor” is being canceled after three seasons.

“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,” Fox Broadcasting’s chairman of entertainment, Kevin Reilly, said in a statement. “We wish him the very best, and it’s our sincere hope that we work together again soon.”

Cowell, 54, is expecting his first child soon, and he said Friday that the decision to leave has left him with “mixed emotions.”

“You (realize) how much you owe to the fans who have supported all of the shows we made in both countries,” Cowell tweeted. “I have had a blast. Really the best time of my life. Thank you for the support and the fun we have had together. It’s never forgotten. We found some amazing talent. And now the search begins to find the next star. That’s why we make these shows.”

Cowell launched “The X Factor” in the United States in 2011 after serving as a judge on Fox’s other singing competition, “American Idol,” for eight years. The newer show had an uphill battle from the start, considering that it was up against both “Idol” and NBC’s talent show, “The Voice.”

It didn’t help that “The X Factor” had a revolving door of personalities as the series tried to stand apart: Paula Abdul, Nicole Scherzinger, Britney Spears, L.A. Reid, Demi Lovato, Kelly Rowland and Paulina Rubio have all joined Cowell, the mainstay judge, on the program.

“X Factor” had just as tough a time securing consistent ratings. According to Entertainment Weekly, “The X Factor” averaged 7.1 million viewers and a 2.3 rating among adults 18-49 on Wednesday nights, an average that includes seven days of DVR playback.

In a statement released by Fox, Cowell said that he’s had “a fantastic time” on both “X Factor” and “Idol” and that “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!).”

Cowell hinted he’s been considering returning to the UK since last year, although his move may not be permanent.

“I want to thank Fox for being an incredible partner and I also want to thank everybody who has supported my shows,” he said. “America, I’ll see you soon!”