Just as fans of "American Idol" are reeling from the news that [article id="1629445"]Simon Cowell will leave the show to begin work on "The X Factor"[/article] after this season, celebrities are also reacting to the announcement.

"Wait, wait, you mean Simon ... he's not coming back?" Denzel Washington asked reporters at "The Book of Eli" premiere. "Oh, I didn't know that. So who's going to take his place? How are you going to have the show without him? Who's going to insult people?"

Meanwhile, Jane Lynch noted that Cowell's attitude will not be easily replaced on the show. "He is Sue Sylvester-esque, and I'll bet I'm stealing a lot from him subconsciously, of course," she said, comparing him to her "Glee" character. "I will miss him. He was wonderful to have in the mix with that kind of acerbic tone. His eye is so good. His comments are always very apt and right on. They may not be said in the most loving way. It's a tough business, and you've got to steal yourself for that. I'll miss him and I hope they will replace him with somebody who can do that sort of thing."

[article id="1629478"]Cowell's "Idol" colleagues[/article] have also been reacting to his departure. Ryan Seacrest wrote on Twitter, "This is Simon's last season on 'Idol.' He's working on U.S. version of 'X Factor'! He is one of the most brilliant people in our biz! Congrats."

Judge Kara DioGuardi told Los Angeles' 104.3 MyFM that she had no idea about the announcement until just before it happened. "He's so important to the show," she said. "I think I was a fan before I was on the show, and he will be really missed."

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