Colin Firth plays a suave intelligence agent who grooms a teen delinquent (British newcomer Taron Egerton) into a superspy in Kingsman: The Secret Service (out Oct. 24). The film — co-starring Michael Caine and a villainous Samuel L. Jackson — is based on the beloved comic book by Kick-Ass creator Mark Millar, itself a riff on Millar and director Matthew Vaughn’s mutual love of old espionage flicks.

“We missed all the spy movies we loved as kids, whether it was Bond or ‘In Like Flint.’ They had a sense of humor as well as being a thriller,” says Vaughn, who dreamed up the idea of Kingsman with Millar over what he calls a “few drunken conversations at the pub.” “With [Kingsman], we’re subversing the spy movie genre as we know it.”

Leading man Firth spoke to EW about the film — the very first action role of his three decades-long career — and spilled details about working on his abs, sustaining injuries (a broken tooth!), and infusing Mr. Darcy into his portrayal of a superspy beyond compare.

ENTERTAINMENT WEEKLY: How did you feel going into your first big action movie, as it were?

COLIN FIRTH: I was afraid it was ridiculous. I think what’s brilliant about Matthew is that he takes people’s expectations and likes to mess with them. When we first met the year before, he said, “One of the reasons I’m casting you is because you’re probably the last person anyone could imagine kicking people and kicking off the villains.” And that was the surprise he wanted to pull. And he said, by the way, “You’re going to have to do it. Are you up to it?” That’s one of the reasons he got me so early, to start training. He said, “You’re going to hate me by the end of it,” and sure enough, the Jackie Chan training team comes to my house and they get to work on me. I don’t think I’ve ever enjoyed myself so much in my life. I realized that I’d made assumptions about myself that meant I had probably been neglecting something that I might have enjoyed for years if I’d got to it earlier.

Did you get a six-pack?

I think that a six-pack, that’s a…bit too far.

A four-pack?

[Laughs] Well, I’ve got a one-pack. At 53, anything that isn’t just a kind of blob of mozzarella just hanging there is something of an achievement. But it definitely changed me enormously. I was thankful, but I was surprised by how much I enjoyed the work. I felt bereft when it was over.

I heard you trained for six months. What was that like? Did you do any martial arts training?

Well, Matthew had me on three hours a day of training, even when I went off to do another film. But it wasn’t eastern martial arts stuff. The guys that trained me were like the League of Extraordinary Gentlemen in that they all had a particular superpower. Brad Allan worked with Jackie Chan. He’s a kung fu black belt and one of the best in the world. That’s his skill. But I also had Rudi Vrba, a Thai boxing world champion, stuntman Rick English, and I had an Olympic gold medal gymnast, Damien Walters. I had a team of people at the top of their field with very special skills coming to me. It was slightly uncharted waters.

Did you sustain any injuries?

Oh yeah, I’d be ashamed to tell you I hadn’t. We were ludicrously proud of our bruises, however small. The first bruise I got, which basically changed the color of my arm, was photographed and everyone said, “That’s going to have to go on the DVD or some website, just to prove that you did this.” And I broke a tooth. I think one of the reasons why Matthew wanted me to do so much of it myself was because of the improbability in people’s minds. You feel anyone can have a scene where you cut to a stunt guy, but because no one expects me to do this, he really wanted to sell the idea that it was me doing it.

What was it like dueling with Samuel L. Jackson?

Well, I’m not going to do any plot spoilers, but I don’t know if that’s exactly the right question. But working with him was obviously a thrill. You suddenly have a gallery of your favorite movies playing before your eyes when he comes into the room. And so I sort of feel, in some ways, I’m finally doing the kind of movie I enjoy watching.

Does any of Mr. Darcy come through in your portrayal of a super cool, old-school spy?

Probably. Yes, I think it probably does. There’s something of me in Mr. Darcy and there’s probably something of that in a lot of things I’ve done. But I think this was one time where we were all quite conscious we used the baggage that people are familiar with in order to create this project.

In the film, your character recruits and grooms a young teen. What was that like, playing what I imagine is a type of mentorship role?

I love it. I love it. I mean, it’s actually one of the things that makes me feel better about growing older. You know, I wondered when I was that age whether I’d end up one of those bitter disappointed old actors who are jealous of young people. I fully expected to be that. But it actually gives me enormous gratification to see how much I’m learning. If someone wants to put me in a paternal role, that’s great, but actually what’s going on in reality is that I’m the one thinking, “I couldn’t do that at that age.” So it’s a two-way process. Taron’s array of skills were so impressive that in some ways, I felt like the student.