So there’s this Norwegian thriller, Headhunters, where the most awful things happen. Heads are crushed, characters are betrayed, and the movie’s hero – who’s not that much of a hero – must plunge into filth and worse to stay alive in the face of an implacable pursuer. But here’s the twist: it’s all really, really funny.

At the Toronto Film Festival last fall, the film’s stars were giggling over some of the awful, awful things they had to do.

“So many of those are from Jo Nesbø’s writing,” says Aksel Hennie, who plays a corporate recruiter and art thief who finds himself marked for death by his latest prospect. “He doesn’t have any boundaries in the way he writes. If he wants to write something, he’ll just write it. It can be horrific, it can be, like, tragic and brutal, and you have to laugh because it’s so over the top but still in a natural setting.”

“I was laughing a lot when I read it,” says Nikolaj Coster-Waldau, who plays the cat to Hennie’s mouse. “I was like, ‘I wonder what they’re gonna do. Oh, that’s interesting.’ It’s got that heightened sense of reality, pushing things a little further. It’s like something crazy happened to you yesterday; when you retell the story to someone, you’re gonna add some colours.”

Hennie, best known as the star of Max Manus: Man Of War, was a friend of Headhunters author Nesbø but hadn’t read his books before making the movie. “Now I’ve started,” he says with a grin. “His way of writing crime is amazing…. You have these strong action-driven thriller plots, but you also have characters, and this humour in the midst of it that makes it readable for me.”

That said, it’s one thing to read about a character comically mutilating a corpse to fake his own death and another to watch someone do it in close-up.

“Some of it actually felt horrible when we did it,” says Coster-Waldau, who’s currently playing Jaime Lannister on Game Of Thrones. “And then when I saw it, I was actually laughing. I mean, it was [still] horrible, but it’s so horrible that it’s funny.”

Audiences at home responded enthusiastically to Headhunters. Hennie says it enjoyed the second-largest opening for a Norwegian film since Max Manus. And that energy has followed them to TIFF.

“I’m feeling a buzz around the film that I’ve never experienced before,” he says. “The international industry is really interested in it, and that feels good.”

Of course, that may have something to do with Headhunters being the new film from Yellow Bird, the production company behind the movie versions of Stieg Larsson’s Millennium trilogy, which gave the world Lisbeth Salander.

“That’s also one of the selling points of this movie,” Coster-Waldau admits, “‘the guys who did Millennium.’ But it’s very, very different. If you laugh at The Girl With The Dragon Tattoo, I don’t think it’s intentional.”