Affleck and Damon walked the red carpet at the New York premiereat the Rose Theater at Jazz at Lincoln Center on Saturday, and spoke with ET about how their friendship has evolved over the quarter-century since their first big project, Good Will Hunting.
For Affleck, the years have seemingly flown by, because he and Damon never really stopped spending time together.
"Over those 25 years, Matt and I have been friends and worked together so it doesn't feel like, 'Oh, I haven't seen this guy in 25 years,'" Affleck explained. "But it is nice! It's cool to be doing another movie with him."
As for working together as co-writers and co-stars on The Last Duel, Affleck marveled, "We loved it, and we definitely want to do more."
Damon, meanwhile, said he's still stunned at the longevity of their careers since Good Will Hunting got made -- both he and Affleck won Oscars for co-writing the screenplay.
"If you told me 25 years ago [that we'd be here tonight], I would be like, 'We made it? We are still working? OK good!'" Damon joked.
Looking back at their first major success with Good Will Hunting and their collaboration on The Last Duel, Damon said it's still amazing how much had to come together to make the films a reality.
"It's a big thing to kind of have an idea and then write something and create something out of thin air," he shared. "Then it takes a lot and you feel a lot of gratitude to the hundreds of people who work on it and make it better."
Damon and Affleck co-wrote The Last Duel, alongside Nicole Holofcener. The film -- co-starring Jodie Comer and Adam Driver, and directed by Ridley Scott -- hits theaters Oct. 15.