The Good Will Hunting stars met at a young age, travelling with each other to auditions in a bid to launch their movie careers.
In their free time, the pair read Marvel Comics and several years later Damon was offered the chance to don the iconic red Daredevil suit for a 2003 big screen adaption.
The hunk declined, and casting directors then turned to Affleck, who accepted the part and went on to fall in love with his co-star Garner.
Joking about competing for the same roles as his pal, Damon tells the New York Post, "I got offered Daredevil way back when. That was the comic Ben and I read growing up. But the script wasn't there. And then Ben did it."
But the 42 year old admits he feared Affleck was making a mistake when he first took on the job: "I was like, 'Dude, why are you doing this movie?' Ben, being the perennial optimist, explained the eight things that needed to happen to fix the script, and he was, of course, right. But he wasn't the director. Although the movie was very successful, it wasn't the movie he wanted to make."
Damon also famously passed on the chance to star in Avatar and Brokeback Mountain. His roles in those movies were grabbed by Sam Worthington and Heath Ledger, respectively.