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Ellen DeGeneres knew Simon Cowell could be harsh, but she says she had no idea just how critical he could be until she recently taped an episode.

"He's actually meaner than I thought," she tells "Entertainment Tonight."

"It's hard to listen to him tell people things and me not to go, 'You poor thing!'"

Reports surfaced last week that Cowell, 50, was already clashing with DeGeneres, 52, who makes her "Idol" debut Feb. 9.

At her first taping, Cowell was more than an hour late (he had just confirmed he was leaving the show after this season) and DeGeneres insisted that they begin without him.

"When Simon showed up, he was p---y that they started without him," a source tells the new Us Weekly (on newsstands now).

But Cowell apologized, and DeGeneres "accepted it right away and was fine," adds the insider.

DeGeneres also is "getting good at delivering bad news" to "Idol" wannabes, she says.

"I'm trying to do it in a tender way," she tells "ET." "I hate hurting people's feelings, so that, I think, is the hardest part."

She says that there are "good people" this season, and she's had to "fight very, very hard to keep the people that I believe in."

Adds DeGeneres, "We have a wide variety [of talent] ... somebody for everybody, I hope."


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