The film, starring Lawrence and Andrew Barth Feldman, hit theaters June 17.
Talk about persuasive!
ET's Rachel Smith spoke to Jennifer Lawrence at the No Hard Feelings premiere in New York City Tuesday, where she revealed how she got her co-star, Andrew Barth Feldman, to defer his studies at Harvard University to take on the role in the raunchy romantic comedy.
"I mean, when Andrew left his audition, the door closed and we all looked at each other and we were like, 'That's our -- that's Percy,' and then they were like there's one complication, he's supposed to go to Harvard, and we were like, 'Is that a joke?'" Lawrence explained.
"He was fully the character, so I called him and said, 'Andrew, I have really bad news you're not gonna be able to finish your semester at Harvard,'" she continued. "He's gonna have to defer, or whatever college school words are."
As for how Feldman felt about putting school on hold, he told ET he couldn't pass up the once-in-a-lifetime opportunity to star in the film.
"Of course," He exclaimed when asked if he still stands by the decision. "Harvard is still there. I can go back, but this movie was once in a lifetime."
He learned a few things from Lawrence too that he couldn't necessarily pick up while at the Ivy League school.
"This is an industry I care so much about; this is a movie I care so much about, and from her, I learned how to be kind and do all of this. How to do all of this and keep a head on my shoulders," Feldman shared. "Let the, you know, the Jennifer Lawrence of it all -- she lets it fade into the background so much. She's a person first, she's a mother first, she's a friend first and that was a huge, huge thing to learn."
He added, "I think getting a stylist and a publicist and all these things I have no idea how to do. We just did a whole press tour together. I learned everything from her. She's amazing."
The funny film sees the Oscar-winner as Maddie, a reckless 20-something who answers a Craigslist ad placed by a pair of concerned parents, played by Laura Benanti and Matthew Broderick. They want Maddie to "date" their son, Percy (Feldman), a socially awkward 19-year-old who has so far expressed no interest in girls, parties or other teenage exploits.
While the film pushes the envelope with some pretty intimate moments, Feldman said the key was for the pair to trust each other, something that was instant for the co-stars from the start.
"It was truly right away. I think there was just something very kindred between the two of us, and day one we were just like oversharing, telling each other our deepest darkest secrets," Feldman said. "There was nothing we were not game for because we trusted, and we trust each other so much."
No Hard Feelings is in theaters now.