Colin Ferrell and Brendan Gleeson in In Bruges Courtesy of Focus Features

"[We] were fairly incubated for those three weeks, just bandying around ideas and talking about the text and what was below it all, the subtext," Farrell says. "So we did garner a greater understanding of the characters. But it kept speaking to us. I thought we would run out of steam before three weeks were up. I thought we would have nothing to do or you would get it to a stage where you had flogged it to death and then we would get up there and it would be repetitious. But the script was so good and so complex that it just kept revealing more questions. The more questions we asked, genuinely, the more that were revealed. So it was an exercise that had no end."

Says Gleeson of their prep time together: "Colin is relentless in terms of bearing down and getting to how suicidal [his character] is. It became a very profound, dramatic thing. Maybe that was a surprise. The psychological exploration became so profoundly dramatic and harrowing so early on. We suddenly began to think: 'God, this is pretty heavy stuff.'"

From Casablanca to Madagascar, films have helped stimulate travel to some of the world's farthest-flung off-the-beaten path destinations. But whether or not In Bruges will generate as much interest in this tiny Belgian town as Crocodile Dundee did for the Australian outback remains to be seen — for one, asking Farrell to "sell" the city of Bruges might be a tough task.

Writer/Director Martin McDonagh (left) with Colin Farrell and Brendan Gleeson on the set of In Bruges Courtesy of Focus Features

"I was bored out of me tits by the first week. Excuse my French. You know, with a lot of places it depends on how you are feeling or where you are. You could go to the same place in two different times of your life and you would think that the place was completely different — it is the energy you give, you project your own stuff. For me, I found it quite stultifying. We arrived in the dead of winter. It was dark every day at four o'clock. And the streets were empty. There was bitter cold gnawing at you," Farrell says, though he does concede that the city itself is beautiful. "There is a majesty that is just jaw-dropping. But there was nobody on the streets, and it was kind of eerie. It felt very lonely."

But, the alienation and loneliness proved useful for Farrell in developing his character's brooding darkness. The actor says both he and Gleeson drew their own inspiration from the city, which, he says, "really is a character — Bruges was the first cast member."

Next up, Farrell stars opposite Ed Norton in the cop saga Pride and Glory written by Joe Carnahan (Narc, Smokin' Aces), and he is attached to Philip Noyce's adaptation of the Tim Winton novel Dirt Music. A sure-fire big-budget summer blockbuster does not appear to be on the horizon, but Farrell refuses to pigeon-hole himself.

Asked if the recent re-evaluation of his acting path will impact the sort of films he will chose, he says candidly: "I don't know. I am not going to limit or box myself in by having a particular structure or code of work. I did three pieces with writer-directors in the last year and a half and enjoyed them all immensely. And I am enjoying this for now. I will see what comes."