“I didn’t know how I was going to do it,” Hathaway tells Entertainment Weekly.

Warning: This article contains spoilers for The Idea of You.

The Idea of You ends with a hopeful, happy moment that doesn’t exist in the book — and it almost didn’t exist in the movie either, according to star Anne Hathaway.

While author Robinne Lee’s 2017 novel about a May-December romance between 40-year-old divorced single mom Solène (Hathaway) and 24-year-old famous boy band member Hayes (Nicholas Galitzine) ends with the two broken up with no hope of rekindling their relationship in the future, the Prime Video adaptation flips the script. The movie doesn’t go so far as to say they “live happily ever,” but Hayes returns to Solène’s art gallery five years in the future, just like he promised, even though she didn’t believe he would. Now that her daughter is old enough to not be as affected by their tabloid romance, and now that he’s no longer in August Moon and has launched a successful solo career, their path toward a happy ending is clear.

But Hathaway tells Entertainment Weekly that she almost couldn’t film the movie’s epilogue, and it was her costar Galitzine and director Michael Showalter who helped save the day.

“The most difficult scene for me was that ending, just because it was the end of the shoot and I’d gotten sick,” Hathaway reveals. “I was not just running on empty, I’d eaten the tank, and I was just physically [doing] poorly, and I didn’t know how I was going to do it. Nick was such a rock.” She turns to Galitzine, sitting next to her, to add, “I don’t know how you did it.”

“And Michael said, ‘I know what to do,'” Hathaway says. “He turned on a piece of music right as he yelled action — because it was a nonverbal part — and [Galitzine] just poured energy in me. I was in the moment and I had exactly enough left for whatever was happening, and I just needed to not blow it. And you just carried us through that and you were so wonderful and you gave me so much to react to.”

Remembering how difficult that day was still brings tears to Hathaway’s eyes today. “It’s hard for me because I … sorry,” she cuts off as she starts crying. “God, I wasn’t expecting that to happen. I like to take care of other people on set, and so at that moment, to feel like I couldn’t even take care of myself, to be supported by Nick and Michael just meant the world to me. It was just really nice.” She stops talking again as she cries more. “Oh my God, this is so embarrassing,” she says with a laugh through her tears.

“No, it’s not embarrassing,” Galitzine tells her. “This was a connective process and I think Annie and I had to rely on each other and Michael a lot. Filming that scene will live with me for a long time because we’re always searching for moments of true presence with each other and true humanity. The fact that it was at the end, was transformative in a way, and it was just Hayes and Solène at their rawest and most real with each other. I’m so proud.”

Galitzine can’t stop praising Hathaway for putting so much of herself into the role during filming. “I was so blown away by her talent, by who she is as a person,” he adds. “We were there for each other, and I think that’s Hayes and Solène — they were there for each other.”

Who says happy endings are only for the movies?