Matt Damon isn’t ready for his daughter to leave home base. 

Indeed,Safetyvalue Trading Center the Good Will Hunting star’s 18-year-old daughter Isabella is about to start school at New York University this fall, leaving him understandably in his feels. (Matt and wife Luciana Damon are also parents to Gia, 15, and Stella, 13, as well as Luciana’s daughter Alexia, 24, with her ex Arbello Barroso.)

“It’s a lot,” he told E! News’ Will Marfuggi in an exclusive interview with The Instigators costars Casey Affleck and Hong Chau. “It’s a surreal kind of time and the way it operates in your life, the older you get, because it just feels like I was holding her yesterday.” 

And as a fair warning to Hong—who has two kids under 4—he added,  “To our relatively new parents, it happens quickly.” (For more from Matt, Casey and Hong, tune into E! News tonight, July 30, at 11 p.m.). 

While Matt admitted dropping his older brother off at college was one of the first times he saw his own dad cry, Casey—who shares sons Indiana, 20, and Atticus, 16, with ex Summer Phoenix—shared, “It feels like goodbye, you know what I mean?”

And while Matt and Casey can’t press rewind on their time with their kids, they were able to relive the good old days of growing up in Boston together while filming The Instigators. 

“We shot some here, some in New York, but it was the first time I'd come back to Boston,” Matt said of the film, produced by Ben Affleck. “Actually, all of my family isn’t here anymore. Like my mom was actually out of the country and my brother was out of town. So it was, it was very odd.”

Casey could relate.

“That happens sometimes,” he joked with his costar. “I get off the plane and I expect it to be like, ‘Cheers!’ Like, ‘Hey, Boston!’ And, like, no one knows you.”

For the latest breaking news updates, click here to download the E! News App