Ben Affleck and Matt Damon credit Kevin Smith for saving Good Will Hunting

Good Will Hunting almost looked very different than the film audiences have come to know and love — and it's thanks at least in part to Kevin Smith.

The 1997 Gus Van Sant drama, written by a then largely unknown Matt Damon and Ben Affleck, follows Damon's hard-shelled foster kid Will, an undiscovered genius working as a janitor at MIT who connects with a rumpled psychologist played by Robin Williams. (Affleck played his decidedly more ordinary best friend; Minnie Driver and Stellan Skarsgard also costarred). The film was a box office success, garnering nine Oscar nominations and winning two — including Best Screenplay.

The longtime friends and collaborators sat down for EW's latest cover, with Damon interviewing newly-minted SAG nominee Affleck about everything from life and love to the early projects that made him a star, including how Good Will Hunting came to be.

"Kevin saved Good Will Hunting," Damon says of Smith (Dogma, Mallrats), who had worked closely with the pair on 1997's Chasing Amy and helped convince the studio that they also belonged on camera. "We were dead in the water. And we would've lost it. It would've been made with other people in it, and we'd still be really angry I'm sure."

Everett Collection

"We would have been the writers, but we wouldn't have been the actors," Affleck concurs. "And the whole thing was we wanted to be actors. And he got it to [executive producer] Jon Gordon and got people to believe in it."

Despite his instrumental role in getting the movie made, Smith might still be waiting for a public acknowledgment. "I promised him I would thank him if we ever got an Oscar, and promptly forgot," Affleck recalls. "And then I told him if I ever win again, I swear to God, I'm going to thank you, and forgot again. So I owe him very much, and he did that. He believed. I remember he wrote me an email at the time and in typical Kevin fashion said, 'I started your movie on the shitter. And I stayed on the whole time.'"

Affleck also credited Williams for signing on to work with a couple of unknowns at the height of his fame: "Now, if you went to do a movie with two first-time guys who were in it and wrote it, you'd have a healthy degree of, 'Okay, how's this going to go?'" he says. "And at the time. he was the biggest star in the world. He was leveraging an awful lot. [But] he never seemed condescending or worried or impatient. He just came into it with this collaborative spirit, embraced it. And it was more him going, 'How was it? What do you think? I think we should do it again tomorrow.'

Mirek Towski/DMI/The LIFE Picture Collection/Getty Images Ben Affleck and Matt Damon

"I'd be [like], 'Robin, you did it 40 times,'" he continued. "'And they were all great! We don't need to re-shoot it tomorrow.' But we'd be back there doing his monologue, and he put his heart and soul into it, [though] I remember personal issues of his that I could tell were coming through in moments. And God, he was a wonderful guy and funny. It was the first time I ever got to hang out with somebody that talented and that famous, and it was quite a thing. I remember walking down the street of Boston with him, and he had done Good Morning, Vietnam and Awakenings and Fisher King and all that. And all everybody in Boston would say was, 'Nanu, nanu. Mork from Ork."

"He would just do take after take after take because that beautiful brain of his would always come up with something different to do," Damon added. "There's a great story Terry Gilliam told me that at the end of The Fisher King, he gave him a report card, which had maybe 10 different categories, like how he was to work with — A! Everything was an A until he got to late-night phone calls, F. Because Robin would call him every night and go, 'Was that okay, boss? What do you think, boss?'"

"And for some reason, he would look to me, and I was like, 'I'm 24, man. You want me to tell you? You're Robin Williams. Why are you asking me for?" Affleck said, laughing. "I'm watching you!'"

Additional reporting by Leah Greenblatt.

A version of this story appears in the February issue of Entertainment Weekly, on newsstands Jan. 21 and available to order here. Don't forget to subscribe for more exclusive interviews and photos, only in EW.

Related content:

• Ben Affleck, at the top of his game

• Ben Affleck's kids love Armageddon — even though 'they relentlessly mock it'

• Ben Affleck credits Gigli for his shift to his 'real love' of directing — and meeting Jennifer Lopez