While Seven Psychopaths features a great script and fantastic direction from Martin McDonagh (In Bruges), the film would be nothing without its cast. Colin Farrell, Sam Rockwell, Christopher Walken and Woody Harrelson each puts his best foot forward in the black comedy crime caper, and it's clear this is a project they care deeply about.

Spinoff Online caught up with Rockwell and Walken, who explained how their great relationship off screen is the reason their chemistry shines through in Seven Psychopaths. Walken in particular looks happier in this film than we've seen him in a long time.

"I think I was probably smiling being with Colin and Sam,” Walken said during a recent press event. “When we're together, we smile. We have a nice time. I think we enjoyed each other, in the movies or on the stage. With actors it's always obvious [if you like each other]. The camera's pointed at it and it gets recorded."

Seven Psychopaths stars Farrell as a struggling screenwriter drawn into a bad situation when his dog-stealing friends (Rockwell and Walken) swipe the prized Shih Tzu of an overly emotional gangster (Harrelson).

Walken and Rockwell previously worked with McDonagh on his Broadway play A Behanding in Spokane, a 2010 black comedy about a man who’s been searching for his missing hand for 27 years. It was then that McDonagh approached Rockwell about playing a role in Seven Psychopaths, which hadn't yet been greenlit.

"It was kind of like reading it on the toilet or something," Rockwell recalled. "I'm like, 'Yeah, right, I hope you get a green light for that. Hope that works out, and when it does, yeah, call me, I'd love to be a part of that.' Is it really happening? You want to know if it's real."

McDonagh told Farrell about the script while the two were filming the 2008 comedy-drama In Bruges and contacted Walken about it after A Behanding in Spokane closed. Once they learned Seven Psychopaths had received the go-ahead, all three were on board.

Although Rockwell was sold on the script from the get-go, he admitted he was uncertain that, as he puts it, they were able to pull the film off. There's one sequence in particular -- we described it in our review -- where he was concerned Seven Psychopaths might lose its audience.

"It was an ambitious movie," he said. "The thing that I was concerned about was the guys in the desert -- the guys being me, Colin and Chris -- talking about feelings kind of throughout. There's a middle section in the desert. I was a little concerned that we were going to lose the audience or not until the next explosion came, and I was really taken with it. It didn't lose me in the first screening that I saw. I was worried about that and I was impressed that that did not happen."

McDonagh's tight script meant there wasn't much room for the actors to improvise, but Walken and Rockwell's experience on stage allowed them to use those words to their best effect. Walken said he finds shooting a film similar to performing a play because both have audiences; in a film's case, it's the crew. Rockwell, on the other hand, said his time as a stage actor helped him relate more to this movie.

"I think stage is the gymnasium for an actor, to work muscles that you don't get to work in film. This film is very theatrical; it has monologues,” Rockwell said. “This is a dialogue-driven film so it's not your usual film. It's like a Charlie Kaufman or a Tarantino or a Mamet; it's got meaty scenes, so it's theatrical. I studied acting and I think there's a great deal of value in that."

Walken repeatedly said he doesn't do much research going into his roles, and that he didn't even look up the definition of a psychopath going into this movie. But he and Rockwell said they didn't think Walken's character Hans was a "psychopath" by the definition of the word.

"In the movie, we are taking a little poetic license," Rockwell admitted. "A typical psychopath does not have any empathy and some of these characters do, so if you look up 'psychopath' in the dictionary I don't know if you'd see Billy [Rockwell's character] and Hans."

That said, Walken explained he found it fairly easy to play Hans. As Rockwell noted, Walken's previous work allows audiences to go in with a preconceived notion of him as a scary actor.

"If you're an actor, you're often seen by reflection," Walken said. "In a way you don't have to play it if other people say so. You turn your back, and they say, 'That guy's totally crazy,' or, 'Oh, the king, watch out, here he comes.'"

Now about that dog. Before the interview we had a chance to meet Bonny the Shih Tzu, and she truly is the sweetest little bundle of love. Rockwell, who has a dog of his own, revealed Walken became quite enamored with the pup during filming.

"That was a great, great dog,” Walken said. “That dog was in every scene, never messed up anything, and she was very affectionate, really good-natured. With animals often there are two or three of them because they get tired, but she would just sit there. Very good-natured."

Rockwell continued, "Absolutely. It wasn't noisy. A lot of those little dogs can be noisy, and it was really quiet and it was really well behaved. It was incredible. We got her to do that paw thing at the end. She's pretty amazing."

Seven Psychopaths opens Oct. 12.