Matt Damon Says His 43-Year Friendship with Casey Affleck Is Based on 'Trust and Love'

Matt Damon and Casey Affleck go way back — over four decades back, in fact.

“We have this 43-year shared history,” Damon, 53, says of Casey, 48, and his brother Ben Affleck in this week’s issue of PEOPLE. “We grew up together.”

The Boston, Mass. natives’ “shared experience and relationship and trust and love,” as Damon puts it, is what makes collaborating on movies like The Instigators (currently in theaters and on Apple TV+ Aug. 9) such a natural process. “There's an underlying understanding of who we are,” he says.

“In our business, there's a whole language that gets created around trying to protect people's feelings because people's egos are involved,” adds Damon. He and Casey “don't waste any time on diplomacy, which I love.”

Damon’s memories of pursuing Hollywood dreams alongside the Affleck brothers in the years leading up to the Oscar-winning success of 1997’s Good Will Hunting included not being “afraid to be vulnerable with each other as young men” in Boston.

“Part of being an actor and putting yourself in those positions and getting rejected constantly — knowing that somebody else is living that same life and making those same sacrifices, that shared sense of experience, that's why we would clump up and hang out together and talk about it,” recalls Damon.