Matt Damon, formerly of the Class of 1992, is one of the few people who can say, “I go to work and there was [Jack] Nicholson in this trench coat and hat, with this giant dildo and he just looked at me and he’s like, ‘I just thought the whole thing would be better if I had the dildo on.’”

Damon, startled by the behavior of the renowned actor, says at that moment on set he thought to himself, “‘Alright, well, I guess I’m along for this great ride.’” In a college conference call including The Crimson, co-star Leonardo DiCaprio echoes Damon’s sentiment of having to stay on his toes while filming “The Departed.”

“We both felt extremely petrified…walking on to the set and not knowing what was going to happen next,” DiCaprio says.

It seems strange that these thirtysomething acting icons would admit to this kind of fear or hesitation. But when considering the pedigrees of director Martin Scorsese and co-star Nicholson, and the hype surrounding this gangster thriller—which might just be “The Godfather” of this generation—the viewer might sympathize with their anxieties.

In the league of screen veterans like Nicholson and Scorsese, Damon and DiCaprio still seem like kids—despite the numerous films under their respective belts and a Best Screenplay Oscar for Damon. Yet “The Departed”—in which the two play challenging roles as men with double identities in the Boston police and crime world—may give Damon and DiCaprio the chance to establish their place among great movie men like Robert DeNiro and Al Pacino.

Ironically, this maturation process required Damon to return to his childhood home—Boston—to film much of the movie. Former Lowell House resident Damon was born in Cambridge, but he never received a Harvard degree.

“I was there for over four years,” he says. “I just kept getting pulled out to do a movie right before my finals, so I’d lose entire semesters. But I feel like I’ve done more than enough course work to get my diploma, but I guess I won’t get it in this lifetime.”

While Harvard has yet to offer Damon an honorary diploma, his experiences here gave him a strong foundation for much of his successful career. He says he is indebted to director David Wheeler of the American Repertory Theatre (A.R.T.) who “earmarked me as a student that he wanted to be a little more invested in.” Damon was an understudy in one of Wheeler’s productions at the A.R.T. before going on to act in his student production of Sam Shepard’s “Icarus’s Mother.”

“Back in the dinosaur times when I was in school…I took a playwriting class that Tony Kubiak taught, and that was where I started ‘Good Will Hunting,’” Damon continues. “ I loved it there; I have a lot, a lot of memories.”

Unlike Damon, DiCaprio had never spent time in Boston before filming “The Departed.” According to Damon, this meant that DiCaprio had a lot more work to do than him and fellow Bostonian Mark Wahlberg, who also stars in the film. The Boston accent, he says, has “been the most often screwed up by great actors who have come to Boston. Leo did a great job with it. And he’s on a very short list of actors who have actually pulled it off.”

DiCaprio says that Damon and Wahlberg were both very helpful and supportive in his transformation to a Bostonian. In addition to spending time with a man from South Boston to master the distinct accent, DiCaprio immersed himself in the history and culture of the city.

“It really is like walking around in a museum. It’s unbelievable,” he says. “The stories that are on the cobblestones of those streets are amazing—following that red line and seeing the Americana that’s behind every…building and really getting an education about American history, which was the thing I did on the weekends. As far becoming a Red Sox fan, I’ve given up on all professional sports after the Lakers sort of dismantled.”

Though Damon may not have needed a dialect coach, he did require assistance in becoming a believable double agent in the police force. As part of his training to play Colin Sullivan, he joined the Massachusetts State Police on a drug raid of a crack house.

“Besides being pulled over on the Mass Pike a few times, that was about the extent of my interaction with the troopers,” the charming and cordial actor says. “You remember that movie ‘The Hard Way,’ with Michael J. Fox? I was kind of like Fox, like ‘Hey guys, can I get a gun?’ And they were like, ‘Shut up, no.’ They didn’t give me a gun, luckily for all of us.”

While Damon may be self-deprecating about his lack of experience as a tough guy, preliminary reviews of “The Departed” highly praise the verisimilitude of his performance. Damon seems poised to join the ranks of Scorsese’s other leading men.

—Staff writer Kristina M. Moore can be reached at moore2@fas.harvard.edu.