Filming “Superbad” wasn’t all happy days.

In a new Vanity Fair article about the making of the 15-year-old high school comedy classic, the cast and crew look back on the testy relationship between stars Jonah Hill and Christopher Mintz-Plasse.

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“Jonah immediately hated him,” says writer-star Seth Rogen. “He was like, ‘That was f**king with my rhythm. I couldn’t perform with that guy.'”

Producer Judd Apatow shares that Mintz-Plasse, who played McLovin in the film, was “very caustic and attacked Jonah and did improvs insulting Jonah” during one of his callbacks.

“Jonah said, ‘I don’t like that guy. I don’t want him doing it.’ And I said, ‘That’s exactly why we’re hiring him. It couldn’t be more perfect. The fact that it bothers you is exactly what we want,'” Apatow says.

All these years later, Hill can now admit, “Chris was really, really amazing off the bat. And I think he was really annoying to me at that time.”

READ MORE: Christopher Mintz-Plasse Opens Up About Suffering ‘A Lot Of Breakdowns’ After Playing McLovin In ‘Superbad’

For his part, Mintz-Plasse says, “It was my first movie, and I was nervous.”

He also recalls the sudden fame he achieved, thanks to his role in the 2007 film.

“I remember the weekend after, going to Chipotle,” he says. “I got recognized, and a girl would climb over my friends to try and touch me. And I would run out of the Chipotle, and all of their friends would run after me. And I’d get in the car and one of the guys put his finger through his pants and was like, ‘I got a boner! I got a boner!'”