Matt Damon and Emily Blunt: The Unlikely Neighbors

Matt Damon and Emily Blunt, co-stars in the upcoming film "Oppenheimer," have become unexpected neighbors in real life. However, there's one thing they've mutually agreed not to do as neighbors: gain weight together. Damon previously cautioned his neighbor against gaining weight for his role in "Oppenheimer," but the advice came too late, as Hartnett had already gained 30 pounds.

Matt Damon and Emily Blunt, two Hollywood A-listers, have an unlikely connection beyond the silver screen: they're neighbors. The co-stars in the upcoming film "Oppenheimer" have become close acquaintances off-set, sharing a mutual respect and admiration for each other's work. However, there's one thing they've mutually agreed not to do as neighbors: gain weight together.

Matt Damon and Emily Blunt: The Unlikely Neighbors

Matt Damon and Emily Blunt: The Unlikely Neighbors

In a recent interview with Fox News Digital, Damon revealed that he had some friendly advice for his fellow "Oppenheimer" star, Josh Hartnett, but it came a little too late. Hartnett, who gained 30 pounds for his role in the film, said that Damon warned him against gaining too much weight, fearing he wouldn't be able to lose it later.

"He gave me a lot of good advice," Hartnett said. "One in particular — one thing that was just so unhelpful: He told me not to gain the weight I’d already gained for the role."

Matt Damon and Emily Blunt: The Unlikely Neighbors

Matt Damon and Emily Blunt: The Unlikely Neighbors

Damon's concern stemmed from his own experiences with weight gain and loss, having undergone significant body transformations for various film roles throughout his career. He explained that gaining weight can be a slippery slope, and it's difficult to shed the extra pounds once they're on.

"He was like, ‘You’re never gonna get that off again, man. Don’t gain weight over 40. You’re going to spend the rest of your life trying to get that weight off and it’s never going to come off because your body is going to want to get that weight back on. You’re just going to keep growing back out to that size, and you’re going to try and get it off, and it’s just going to go back.’ He kept telling me over the course of production."

Matt Damon and Emily Blunt: The Unlikely Neighbors

Matt Damon and Emily Blunt: The Unlikely Neighbors

Hartnett, with his tongue firmly in cheek, joked that Damon's advice was "unhelpful," especially since he had already gained the weight for his role.

"I was like, ‘Thanks, Matt. Thanks for telling me this now. I’ve already gained it,’" Hartnett quipped. "And now I don’t eat anymore."

Despite Damon's cautionary advice, Hartnett has been able to lose the weight he gained for the role, crediting a combination of diet and exercise. He also joked that the pressure was off during awards season, as he wasn't up for any awards and could simply enjoy the festivities and support the film.

"It is kind of fun when you’re not up for any awards," he said. I just get to have a couple drinks with people and hang out and watch other people go up there and give speeches and make a fool of themselves and it’s great."

Damon and Blunt's neighborly bond is a testament to their mutual respect and admiration, both on and off the screen. Despite their agreement to avoid gaining weight together, their friendship and support for each other's careers is evident.