Why did you each want to play the character you did?

These characters are two sides of the same coin in a lot of ways. They come from different backgrounds, but they could have easily made choices the other character made, depending on the circumstances. It just sort of happened that way. I suppose Marty (Martin Scorsese) and I got the script first, and Matt (Dillon) was the next guy onboard, and it was ultimately Marty’s decision.

What are your influences for performing that kind of violence?

I guess by watching Martin Scorsese movies, right? Well, it’s not really familiar to me, that form of immediate violence. But that’s what you do as an actor. If you can’t draw upon anything in your real life, you go meet people that have done these sorts of things. And part of the process for me was going to Boston. I’d never spent any time there, so learning about the Boston sub-culture, meeting some of the real people that were around during the late 80s during the sort of Whitey Era, we may call it. Boston’s a very interesting place because everyone knows each other’s business.

How much do you know about the Hong Kong version, and are you familiar with Tony Leung and Andy Lau?

We all watched and we all enjoyed the film. But I think we had to separate ourselves from it to a certain extent. You know what I mean? Certainly, the concept and the skeleton of this story is very similar in this version. But it’s dealing with an entirely different underworld.

What is it about Martin Scorsese that attracts you to his films?

Leonardo DiCaprio with Matt Damon in The Departed

I’m a fan of his work, number one. The truth is that I suppose it all started, for me anyway, wanting to work with him doing This Boy’s Life with Robert De Niro and getting familiar with Robert De Niro’s work. Obviously, that would mean Martin Scorsese’s work as well. So, I became a fan of his work. And at a very early age, if you would have asked me who I wanted to work with at 16 years old, it would have been this guy right here. And I got fortunate enough to work with him on Gangs of New York in 2000. And I think just from there, I don’t have an exciting term for it other than, we have a good time working together. And we have similar tastes as far as the films we like. He certainly has broadened my spectrum as far as films that are out there in the history of cinema, and the importance of cinema, and really brought me to different levels as an actor. I look at him as a mentor.

How did you come to appear in this film?

I just received the script, and it was really Bill Monahan’s work here, this tightly-woven, highly complex ensemble piece, this gangster thriller. It’s very, very rare, I must say, in this business, where a script lands on your lap that is ready to go. And this was one of those rare occurrences. There was a certain amount of work and there was, of course, character development and bringing certain things out and changing dialogue. But to have the construct of a story there, and to have highly complex characters, duplicitous characters, information, disinformation, plot twists, and everything coming to a satisfying ending, is something you hardly ever get in this business. I think I got this script around when Marty got the script, and we just talked to each other, and it was one of those things we didn’t really need to discuss. He wanted to do it; I really wanted to do it; and for lack of a better term, the rest is history.

You and Matt don’t share much screen time, but your characters are very similar...

They’re like two sides of the same coin. It’s true. They’re products of their environment, and they make certain choices early on in their lives that affect everything for the rest of the film. But, for us, I think the working experience was interesting because it’s almost like we were shooting two entirely different films. Of course they intersected at moments, but they were two entirely different films and two completely different experiences. I suppose that the link would be Vera’s character and, of course, Jack Nicholson’s character. But it was interesting to intersect the different pieces... The moments that I did have with him, he’s an unbelievable actor, he really is.

What was it like working with Jack?

It’s one of those situations where you would entirely expect Jack Nicholson to come on the set and to do something unpredictable. And that’s what he did. I mean, that was part of the nature of him playing this gangster. There are certain things that aren’t written on the page, but when you bring someone onboard like Jack Nicholson, he’s going to take it automatically to the next level. It’s just going to happen inherently. And that’s why he’s continued to do such amazing work throughout the years, and that’s why people are still constantly interested in seeing what he does up on screen, because it’s that level of unpredictability, constantly.

In early discussions that Marty and I had about it, we kept on coming back to God, who could be great as Costello? Who could take this to that level? And we kept coming back to Jack because we knew he could bring it to that level that it needed to be brought to.