Elaine Cassidy and Cillian Murphy are faced with a dilemma. The young Irish stars of the film Disco Pigs, a powerful tale of obsessive love and bone-splintering violence set in Cork, appear unsure as to how Irish they should allow themselves or the film to be. Indeed, any questions about the Irishness of the project are met with mild irritation: "A lot of people have been asking us about that," explains Elaine. "And to be honest it's annoying, because it just happens that the story takes place in Ireland, but really it's a love story that could have happened anywhere in the world." It could be the jet lag talking. Elaine, who looks Irish enough to go on the back of the five punt note, just flew in from Canada where she is filming, for the Dublin premiere of Disco Pigs. Though tired, she is deeply pretty and utterly delightful.

Similarly, Cillian has jetted in from London where he is also filming. Slight and brooding, he is one of those Napoleon types: only 5'7", but somehow bestowed with a much larger presence. He instructs the hairdresser on the correct way to brush his hair, worries that the clothes the stylist has brought may be too "fly", and then slithers into a constricting black suede trench coat from Yves Saint Laurent women's wear collection. "It's like a corset," he half complains, before retreating to a corner of the studio to rap out the rhythm of the Talking Heads hit Psycho Killer, in an impressively mad-actor fashion. "There is no real sense of geography in Disco Pigs, and no cultural references that shout 'This is Ireland'," Cillian continues. "And there are none of the clichés you find in Irish films - no sweeping landscapes, no poverty, no church." Point taken. Disco Pigs is not your typical Irish film. Adapted from Enda Walsh's hugely successful stage play about mutually obsessed teenagers whose passion explodes into violence over two fateful evenings, it is difficult, quirky, and occasionally downright queer.

Elaine plays Runt (real name Sinead), a mystical and misguided young woman who is searching for her place in the world. Cillian plays Pig (Darren), a violent, psychotic youth whose world centres entirely around Runt. Born five minutes apart, they first meet in an antenatal ward during a remarkable sequence in which two newly-born appear to act. They grow up living next door to each other, dress identically, walk to school together, and even share a telepathic link. Pig and Runt, the self proclaimed King and Queen of Pork Land, create a world of their own, emerging only to run amok in the real world. At no point in Disco Pigs does it rain for picturesque effect. Nor are we treated to even the briefest snatch of wistful uillean pipes. However, there are seascapes aplenty here. And much of the language of the piece, a fusion of lovers' childishly abbreviated syntax, scatological babble and achingly visceral poetry, owes a debt to Joyce's Ulysses. "Of course, there is some truth to the Irish stereotypes," admits Cillian. "The people are very warm and friendly, and rural Ireland does have a real charm and beauty. But Pig and Runt live a suburban life, so to go to the sea is quite a big deal for them. They don't know how to react to it."

Like the country itself, which has recently undergone a sweeping cappuccino revolution, Disco Pigs is torn between the old and the new Ireland. In Dublin, for example, you can buy Prada on Grafton Street. Yet, only seven minutes away on Camden Row the butcher's shops smell of tripe and sawdust and children brawl outside the pub. One can understand Cillian and Elaine's reluctance to identify completely with their homeland. Both are clearly poised on the verge of great things, and neither wants Ireland's formidable cultural gravity (which holds Father Ted, Riverdance and the fiddletastic Corrs in close orbit) to hold them back. "If anything, being Irish is a hindrance," insists Elaine. "The majority of films are not about Ireland. I've never yet acted in my own accent."

Elaine, 22, first reached an international audience with the title role of Atom Egoyan's acclaimed Felicia's Journey in which she played a naive Irish woman abroad. Raised in the small village of Kilcoole, North Wicklow, her acting career began with a role in the now defunct RTE soap opera Glen Roe. "I was only in it for five episodes," she says. "I played a bad girl, and I think I was the first teenager on Irish television ever to smoke. But thank God I didn't sign the contract with them, because if I had I wouldn't have been able to go off and do Felicia's Journey." And Elaine has been simmering away nicely as the next big thing in Celtic actresses ever since. In fact, this is proving to be something of a breakthrough month for her as she also appears in the suspenseful Nicole Kidman movie The Others. Nicole was "lovely" to work with, says Elaine, who plays her mute maid in the film. But real lure of the job was the involvement of acclaimed Spanish director Alejandro Amenabar. "I really wanted to work with him, ever since I saw Open Your Eyes," she enthuses. Elaine likes her movies independent.

At 25, Cork-born Cillian is already considered one of the hottest actors in irish Theatre. One year into a law degree at the local University College he blagged an audition with the Corcadorca Theatre Company, and was taken on. There he originated the role of Pig for the stage production of Disco Pigs in 1996 and toured worldwide in the part for the next three years. "It was a great experience," says Cillian "But people would never come up to me afterwards and say 'well done, that was fantastic'. In fact they used to steer well clear of me." Cillian is currently filming in London with Trainspotting director Danny Boyle, on a script written by Alex Garland (author of The Beach). "It's a sort of sci-fi horror film called 28 Days After," he explains. "I play someone who wakes from a coma to find the world completely changed. It's hard to describe, but it's a bit like Day of the Triffids." It's the sort of break that young, ambitious actors dream of, and Cillian isn't taking anything for granted: "I really wanted this part," he says. "I really, really wanted it."

Disco Pigs makes for intense viewing, but Cillian and Elaine are keen to make light of the filming, which took place in Cork and Dublin over seven weeks last year. "There is an obvious tendency to intellectualise the film," says Cillian. "But really we just had a laugh and got drunk a lot." They both smile. "We all stayed in a big hotel," Elaine continues. "My room had three huge gothic windows, which was great for atmosphere. But I nearly went mad some nights just wanting to make a sandwich or something." Of course they are being conspiratorially disingenuous, just as Pig and Runt might be. In truth, the filming was no giddy bender. Kirsten Sheridan, who makes her directorial debut with Disco Pigs, praises Cillian's perfectionism and focus; "he has an amazing work ethic." Equally Elaine embraced her role: "she doesn't put up barriers," says Kirsten. Cillian's biggest challenge was to unlearn everything he had developed for the staging of Disco Pigs - to create the character anew for the camera. "I had to throw the play away," he admits. And there were times when Elaine's emotions got the better of her on set. "I got so attached to the film, that I found the end really sad and I was breaking down inside," she explains. "I had to fight back sobbing and falling apart four times." And of course they have both been intellectualising their heads off developing scads of theories about the devouring relationship that consumes their characters. "They're like Siamese twins, and they can only survive together for so long," offers Elaine. "It's a love story taken to another level." Adds Cillian. "They're not just lovers, they've grown up together, so it's like the most intense relationship you can imagine." Kirsten thinks that they could be closer even than that: "some people see Pig and Runt as mystical brother and sister, so when he lusts for her it is like incest."


Viewed in this light, Disco Pigs becomes darker, and somewhat more satisfying work. It explains why the people around Pig and Runt find their closeness, their special language and their occasional telepathy so very unacceptable. Otherwise, we have to surmise that only in the west of Ireland would a young woman be sent away to an institution, as Runt is, to protect her from a bad influence. Then there is the matter of Runt's infidelity to Pig. She in the only one of the two to form relationships outside their womb-like world, first with a classmate on whom she develops a crush, and then with Mags, a girl she meets at the institution. In an exquisitely filmed scene, Mags sets fire to their shared bedside table to the strains of a female duet from the marriage of Figaro. But, says Kirsten, if this is a lesbian moment it is an unintentional one. "I chose that piece of music because I heard it in the Shawshank Redemption. I just wanted something with two women singing, because this is the first time that Runt has been able to have a platonic relationship. Some people have picked up on the lesbian thing which is fine. But we didn't." And therein lies the rub. For if any criticism is to be made of Disco Pigs it is that, at times, it is rather like the irritatingly prim friend who holds back for the sake of some abstract notion of self. Sometimes Disco Pigs appears on the verge of being very funny, but then isn't, and the violent and sexual content of Enda Walsh's play has certainly been scaled back for the big screen. "We didn't want to make a cool, violent film like the new Trainspotting," defends Cillian. "It is a much more delicate script than that." Still, at times you want to shake the film by the shoulders. But this is purely hypothetical quibble because, for the most part, when Disco Pigs lets rip, it does so with commitment and power. As a showcase for the burgeoning talents of Cillian and Elaine it could hardly perform better, and in the final analysis, it packs a punch that will quite literally send you reeling. "Disco Pigs is like a cross between a Greek myth and a mental Irish Ceilidh. It's about extreme love and extreme violence," says Kirsten. "There are things beneath the surface of all Irish people. But you do see them... especially when the people get smashed."

Disco Pigs is released on November 16.