THERE ARE plenty of reasons to recommend Jon Wright’s new Irish comedy-horror, Grabbers. It features excellent sea monsters. It includes an effective opposites-attract romance. And it foregrounds some of the most extraordinary drunk acting you could ever wish to see. It’s not just the quality of the boozed-up performances that attracts the attention. Their sheer girth is remarkable. For the last third of the film, the residents of a small Irish town – having realised that the advancing aquatic beasts are allergic to alcohol – fight their battles in a state of serious intoxication.

This offered Ruth Bradley a serious challenge. The Irish actor, now 25, has, of course, acted drunk before. But a full 20-minute stretch of slurring and falling over is not something that you get in the average Noël Coward comedy or Shakespeare history play.

“It’s almost half the film,” she confirms. “That did offer a lot of challenges. She spends a lot of the time drunk, but not much sitting in the corner drooling. I had to make it funny and also realistic.”

The director eventually suggested that some serious research might be in order.

“Nobody knows what they look like drunk,” Ruth says. “So Jon asked how I felt about having a few drinks and then filming it. We’d then have a kind of visual short-hand for what you would look like. We were going for that first-time-drunk thing: very happy then very sad and nothing in between.”

Did she suffer for her art? “It took me about two days to recover.”

Nobody could fault Bradley’s commitment to her art. The daughter of Charlotte Bradley, a distinguished actor, Ruth can’t remember ever wanting to do anything else with her life. As a young kid, she secured a role opposite mum in Passion Machine’s well-remembered production of Buddleia.

That Paul Mercier play toured Poland and played at the Donmar Warehouse in London.

“I was playing the child of a drug-addicted couple,” Bradley remembers. “It was an amazing experience. I got to talk to this huge cast and ask them all these questions about the work. I think I was a very precious kid. I think, when I was about 12 or 13, I started complaining: ‘I haven’t worked for ages.’ Awful.”

It was always her intention to make for London when she left school, but, having achieved decent results in her Leaving Certificate, she was persuaded to study drama and languages at Trinity College Dublin. Is it true she only lasted three weeks?

“That is true. I gave it a real go,” she laughs. “I had been touring with Druid in John B Keane’s Sive before that. For a brief moment I thought: yes, I should have something to fall back on. But I quickly realised my heart wasn’t there. I wanted to go to London and act. So I said: ‘Thanks very much, Trinity. You are brilliant. But I have my plan.”

She really is a gently frightening piece of work. Softly spoken, inclined to the odd throaty cackle, she sounds like the well-

brought-up, middle-class Dublin girl she is. But there is clearly a shard of steel in her soul. Just 18, she headed to London and committed herself to the profession. While her pals were making their first trips to the pub, she was working in call centres, living off rice and sleeping in a bedsit.

“It has never been harder than when I first moved over,” she says. “I would occasionally ask myself what I was doing. I would meet older actors in these telesales jobs and they’d be saying: ‘Oh, I hope my agent phones.’ All that was very depressing. But I felt that if I could get through that first year then life would never be so hard again.”

So things proved. Ruth fairly rapidly scored supporting roles on TV. In 2006, she had a small part in the American war film Flyboys. In the current decade, she has taken regular roles in three series: ITV’s science-fiction romp Primeval, the hit RTÉ thriller Love/Hate and the historical drama Titanic. She has recently returned from the United States where she signed a contract with ABC television. Most actors admit to insecurity about their professional position, but Ruth does seem to have found herself in a reasonably secure position.

“There are still challenges,” she says. “ I don’t want always to play the Irish character. Now, I want to do something different. I don’t think I have, in this business, ever sat back and thought: I am comfortable.”

Do people recognise her? Once you are on the telly people seem to think that you are their friend. Ruth isn’t exactly a star. But she has appeared in viewers’ living rooms on a fairly regular basis.

“It is interesting,” she says. “People do feel able to approach people from the TV more easily than film actors. TV actors are actually in their homes. You have to go out and pay to see a film actor. People sometimes think they know me, but usually they think it’s from seeing me in the shop down the road.”

On paper, Grabbers sounds like an unlikely project. Shot on a modest budget, the picture casts Ruth as a Dublin-based Garda who, after relocating to the west of Ireland, finds herself gently at odds with her new partner. Played dryly by Richard Coyle, he turns out to be a boozy (but decent) layabout with unresolved personal issues. Ruth’s character is uptight, fastidious and polished. As she arrives, strange, violent doings are afoot. Man-eating sea creatures are soon everywhere about.

“I got the script, read it and thought: this is a romantic comedy,” she says. “I really didn’t notice the creatures. It’s about two people. I thought it was very good, but I knew it could go ether way. I didn’t want it to be stage Irish. But it turned out the director knew his stuff. He had his head screwed on.”

The producers have done a good job of rolling out the movie. It played at the Sundance Film Festival, still the key spot for independently minded cinema, before moving on to the Edinburgh Film Festival in June. The picture picked up strong reviews at both events. Sundance must have been a particularly delightful experience. A great many celebrities touch down on that one, very small patch of Utah soil.

“It’s weird because it’s so normal,” Bradley says. “It’s all in one street. It’s like a country town in the west of Ireland. But John Hawkes and Paul Giamatti are walking down the street. Everybody is so normal. There’s no fuss. And the quality of films is always really good.”

And the Americans got it? Much of the humour is very Irish. The accents are very thick. “It’s funny, they loved it. But they laughed at completely different points,” she says. “They laughed at things we never thought were funny. So much of it is dry. But they got it.” It was worth the hangover.

* Grabbers opens today