The duo, who have been friends since childhood, won an Oscar in 1998 for their debut film script, in which they starred alongside Robin Williams and Minnie Driver.
They have come together again almost 25 years later to write The Last Duel, alongside acclaimed writer-director Nicole Holofcener, in which the pair star alongside Jodie Comer and Adam Driver.
The film, directed by Sir Ridley Scott, tells the story of France’s final trial by combat, recalling the events from three different perspectives – the husband of a woman who says she has been sexually assaulted, the alleged assailant and the woman making the claim.
Affleck said it was “a very deliberate thing”, that the film would have modern comparisons, adding: “Part of what we wanted to point out was the extent to which corrupt and morally bankrupt, and misogynist, institutions create and produce people who reflect those values.
“So rather than just an indictment of a bad person, a bad man, to say, ‘Look, you have the church, you have science, you have the court, you have this whole Western-European civilisation, of which we are an antecedent, culturally.’
“At least, that’s the notion of the United States, that it’s the result of the Enlightenment and its philosophies, even though it’s actually not true.
“But the idea is here this predominant culture comes from this other culture, that is what produced these values, in terms of how it educates people, and in terms of what it rewards, socially, in terms of the behaviour that is encouraged.
“In the character that I play, l could have been just a complete villain. But my hope was, yes, he’s a villain, he does horrible things, but really, the idea is that when a person is in power, and represents these values, and says, these are the values we encourage in you, and you’ll be rewarded for following them.
“People can be changed and created by these large institutions. And that’s the value system that we wanted to indict.
“But then you have to just throw it away and hope that the great actors make you identify with the people so that none of that feels pedantic or like your sermons or like a term paper.”
Addressing why it took so long for them to write together again after their huge success with Good Will Hunting, Damon said: “I think we were kind of afraid of writing, because we were so inefficient.
“It was so time-consuming the first time we did it because we didn’t know what we were doing, and it took us literally years.
“And we wrote thousands and thousands of pages that we basically scrunched into a 130-page screenplay.
“But I think by doing movies for 25 years, just kind of by osmosis, we figured out structure.
“So it turned out to be really efficient, the process, and also begging an incredible writer like Nicole to come help us was also a really good idea too.”
Affleck and Damon penned the two parts of the film told from the men’s perspective, while Holofcener wrote the third part, told from the perspective of the woman, Marguerite de Carrouges.
Damon said: “The construct was that the world of women is totally ignored, and overlooked, and is invisible for the first two acts of the movie. And then it’s revealed in the third act.
“Ben and I were adapting a book but Nicole was really writing an original screenplay, because the men of the time took very fastidious notes about what they were all up to, but they didn’t record what the women were doing.
“So Nicole really had to create Marguerite’s world, out of whole-cloth.”
The Last Duel is released in UK cinemas on Friday.