Colin Farrell: Naughty but nice

Colin Farrell is a little tired today. The stubble has rebelled and declared itself an early-stage beard. The strong, thick eyebrows are starting to reach out to one another for support, giving him a slight scowl. He's been out on a five-week bender back in Dublin, his home town, where both his latest film The Recruit (see Anthony Quinn's review) and his next, Phone Booth (out in a few weeks), were showing in the Dublin Film Festival. But there's something more than tiredness about him. Something in his eyes put you in mind of a man who's just crossed a bridge over a ravine and seen the ropes and boards collapse behind him.

There's no going back now. The 27-year-old actor has been praised for his work in films such as Minority Report (in which he's cast against type as a repressed ex-priest), and Tigerland (playing Bozz, a rebellious but noble grunt). But that's not what makes him news. There are paparazzi downstairs stationed at every exit to snap at him when he leaves. Everyone wants to know who he's snogged recently, apart from Britney Spears and Demi Moore; who he's dating (apparently Kate Beckinsale); and what's happening with Kim Bordenave, themodel who's pregnant with his child.

Maybe he's just arrived at the stage – the one after you've been on the cover of Vanity Fair, but before you start taking swipes at photographers – where the whole circus isn't an amusing novelty any more. Farrell is already legendary for his pugnacious frankness about his exploits, happy to talk about past drug-taking and brawls, and the varying shapes of pubic hair around the world. Does he regret some of the things he's said now? "No," he insists. "A couple of times I've read things and maybe for 30 seconds I get a panic attack and think, 'Oh my God, did I say that?' and then I say 'Yeah, I did, whatever.' Josh, my agent, who is a fucking bitch at the best of times, once wrote me a nice little note saying, 'A few industry insiders have commented on this [a particularly scandalous interview] already. If this is how you want to be perceived in the industry, so be it.' I told him to fuck off."

But he is learning to declare some limits now. Today he has his brother Eamon in the room, whether for moral support or to keep an eye on the questions, it's not clear. I ask whether being a father will change him. No, he insists, but it will be the "most important thing that's ever happened to me," and no, he's not with the mother as a couple. Then he asks if we can give this line of questioning a rest as he's already talked about this a lot over the past few days. Which question have people asked about more, I wonder aloud, the baby thing or the heroin quote? (He was accused of condoning heroin, based on an interview he did for Playboymagazine.)

"No, you're the first person to ask about the heroin," he says. "I was just taking the piss, completely. The journalist said, 'What about heroin?' and I said, 'Heroin is fine in moderation.' And he didn't put in brackets. Left it as a quote and all of a sudden at home it was, 'He condones the use of...' That's the problem with print. The people, it's up to them to do you a favour or not, and he decided not to. Sitting in my hotel room in Los Angeles one night at 3am, I decided to call up The Gerry Ryan Show, [a morning radio show in Dublin] and I talked to Gerry for about 45 minutes and cleared a few things like that up. I was out of me head and had a brain fart," he says and mock mumbles drunkenly.

"Brain fart" is a phrase Farrell uses a couple of times in the interview, suggesting a thought that bubbles up and passes idea-gas. He uses it when I ask if he improvises on screen, as in: "Every now and then you have a brain fart, you know, something will come out of your mouth. If I try to improvise when I'm playing an American character I'm stuck, because I haven't prepared the words."

At least he had a chance to busk a bit on Daredevil, since he used his own accent for his leering baddie Bullseye opposite Ben Affleck's uptight superhero. You have to admire the preening relish with which he says lines like "You're good, baby, I'll give you that. But me? I'm magic!"

In "real" life, as it happens, he's happier praising others than himself. He says he's learnt something from everybody. Working with Al Pacino on The Recruit was an honour; Max von Sydow, his co-star on Minority Report, is a "living legend – something of a European Pacino". Steven Spielberg was "cool". Tom Cruise wasn't the don't-talk-to-me stand-off he was rumoured to be, although he might of gotten a little annoyed with Farrell one day when he kept fluffing a line on set after celebrating his birthday the night before in style...

But you can tell the man he really feels boundless love towards is Joel Schumacher. A window-dresser turned costumier turned director of reams of Hollywood schlock, Schumacher suddenly became a credible auteur when he made Tigerland, a scratchy, sensual low-budget film set in a boot camp during the Vietnam War. He cast the then practically unknown Farrell (who'd been in Ballykissangel, and had small parts in The War Zone and Ordinary Decent Criminals) and that was that, a star was born. Farrell still lists Tigerland and Phone Booth, his second with Schumacher, as his favourites out of all the films he's made.

"I learnt a lot off Joel about integrity and being a decent person and knowing the irrelevance of all the trimmings. What a life! He's been there, done that, bought the T-shirt, ripped it apart, restitched it. He's looked after me from day one and I know, if I ever get in a jam, who I'll get at the end of a phone. His life has got to be put down in a book if he can remember half the shit he's done; that's a good read." Eamon chips in: "It will be volume one, volume two, volume... Colin agrees: "It would be like Ulysses, man – you'd need a little instruction manual on how to read the thing."

Schumacher has fashioned Phone Booth around Farrell like a perfectly cut suit. The actor is on screen nearly every minute, and it's easily his most dazzling performance, playing a smarmy publicist who is trapped in a New York booth by a sniper who will shoot him if he gets off the line. The emotional climax has Farrell crying and confessing his sins to the assembled onlookers as his last bit of swagger trickles away.

Was that a hard scene to shoot? "Oh yeah. It was on the second-to-last day and by the time we did it I was just spent emotionally and my head was wrecked." He does some mock bawling his eyes out and then laughs at himself. "It was the first take that morning. Joel, the understanding soul that he is, said we'll start the camera right back and as you get more into it throughout the day we'll get closer and tighter and tighter. Right on the first take – [he untranscribably starts blubbering like a baby] – and the camera was 150 yards away."

Looking thoughtful, Farrell notes that so far his performances have been "nowhere near" as good as he'd like. Presumably that includes his turns in the action movie S.W.A.T with Samuel L Jackson, and two Irish-set films, Intermission and Veronica Guerin, all yet to be released. A self-described "liver-in-the-present", he's more excited about his next project, an adaptation of Michael (The Hours) Cunningham's novel A Home at the End of the World.

In it he plays a straight man, who nevertheless sleeps with his best friend. "His best friend is gay, he's not, but when they're young they mess around with each other. His family have all passed away, so he's had a lot of loss in life but he's not really that damaged by it. In The Recruit I played a character who's lost both his parents at 14, and it's like an internal scar he wears every day of his life, but this character is the complete opposite, he's really open and full of love. It's a beautifully written character, so I'm a lucky little bastard getting a chance to do it."

It's a small independent film this time, I say. "Yeah, I think there's $5-6m in the budget," Farrell reports, before volunteering, "and just one scriptwriter, which is nice." Weren't there a number of them on The Recruit, I ask. "Yes," he says with a wink. "And there were a number of them on a number of them [films he's made]. It's not an irregular thing when a film comes out of Los Angeles or the studio system that they're paying writers to do more treatments, to fix and doctor things, and it just gets muddled. And you haven't got one clear vision or one passionate overview."

No sooner will he finish that then he will probably start shooting Alexander, a biopic of Alexander the Great, with Oliver Stone, another strong man Farrell admires. Has he partied with Stone? "No, he's keeping a low profile. He's been waiting a long time for this. He's a fucking interesting dude and he's a smart man and he has shit to say."

I wonder if Farrell has shit to say too, (apart from saying "shit" and "fuck" all the time). Does he want to direct himself eventually? "Maybe someday," he says casually. "I'm still trying to figure out this acting thing big time. It's still stumping me every time I try and do it. But maybe someday yeah, in Dublin or something."

Clearly, he has more than enough on his hands these days. "There's days when you come into work and because there's stuff going on in your personal life, your head is there but also a little bit somewhere else," he concludes. "You put a lot of energy into hiding because you don't want to be asking or talking. There's a mood inside you that you can't shift and you just have to keep that away and focus on getting the job done." After all, there's no going back.

'Phone Booth' is released on 11 April