Alyson Hannigan on Her 'American Reunion' Male Co-Stars: 'They Regress Not Even to High School but More Like Junior High' (Video)

The "How I Met Your Mother" actress also told THR that she never expected to star in any more films after the first "American Pie."

Alyson Hannigan’s character in the American Pie movies, “one time, at bandcamp” Michelle, is one of the most memorable characters in the teen comedy franchise, but it turns out that Hannigan didn’t expect to be in more than the first movie – let alone four of them.

“In the contract for the first one it was just a scale-plus-10, it was a minor part,” she told The Hollywood Reporter at the premiere for American Reunion, which opens in theaters on April 6.

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She added that her contract had originally had a sequel clause in it. “I was like, ‘My character wouldn’t be in the sequel because she leaves at the end,’” she said.

But here she is, starring in the fourth film in the franchise. “I totally did not expect ever to be in more than just the first one,” she told THR.

Her character in the Universal comedy, Michelle, has grown from an awkward teen to a married (to Jason Biggs' character Jim) mother.

“She’s still her quirky self, but she is probably a really good foundation for Jim’s craziness,” he said. “They’re like the perfect couple really.”

The entire original cast including Jason Biggs, Seann William Scott, Mena Suvari, Tara Reid, Chris Klein, Thomas Ian Nicholas, Eddie Kaye Thomas and Jennifer Coolidge will appear in the fourth installment, which is directed by Jon Hurwitz and Hayden Schlossberg. The story follows their characters as they head back to their hometown for their 10-year high school reunion.

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“You get those boys together and they are boys,” Hannigan told THR. “They are like throwing things at their crotches, and there’s lots of burping.”

“They regress not even to high school but more like junior high,” she added.

Hannigan also stars on the CBS comedy How I Met Your Mother as Lily. Her character is currently pregnant, as is Hannigan in real life. She’s expecting her second child with husband Alexis Denisof. She showed off her baby bump at the premiere by wearing a curve-hugging sleeveless green minidress.

“It’s very convenient,” she said of having her character pregnant at the same time. “Although Lily is farther along then I am, so I do occasionally have to wear a pad, which is a little restricting.”