So what's taking them so long to act again together?
"It would have to be something that we felt was really worthy of getting made," Damon told me earlier today while promoting his new fantasy action flick The Great Wall (in theaters on Feb. 17). "We'd love to work together again and we have a company together and we develop stuff together, but to find the right thing is tough."
Being best friends is enough to make a good movie. "You don't just work with your friends," Damon explained. "There's gotta be the right thing. It's gotta fit."
Affleck also gushed about producing Manchester By the Sea, which is up for many Oscars, including one for Casey Affleck.
"I met him when he was five," Damon says of the younger Affleck. "It's wonderful, it's great. But I've felt for 25 years that he's one of the best actors on the face of the earth. And so, it feels so deserved, and so earned. Ben and I both are really thrilled. I just saw Ben the other day for the Super Bowl, and we were talking about how excited we are for him because he's really put in the work, and he's a great actor. And that performance is a great performance. It really is everything I love about acting—it's subtle, but it's real and it's still incredibly interesting. You can't take your eyes off him when he's onscreen, but he's not showy."
One of Damon's next projects is co-producing Witness for the Prosecution with Ben, who will also star in the adaptation of the Agatha Christie novel of the same name.
Damon smiled, "I just try to work with the Affleck brothers as much as I can. "