Once, a stunning new Irish film opening nationwide on May 18, tells the tale of a Grafton Street busker and a Czech immigrant who come together over an eventful week to write, rehearse and record songs that bring their unique love story to life. CAHIR O'DOHERTY reports.

AS the two lead roles in the exciting new Irish film Once get to know each other, sparks fly and new songs are written. But this is no by the numbers boneheaded musical, but rather a gritty and realistic story of modern Dublin and the dreams of two immensely talented hard working people who live there.

Cillian Murphy was originally slated to play the hero, but when that deal fell through the role was taken - very reluctantly - by the lead singer of the celebrated Irish band the Frames, Glen Hansard, 37. It was a stroke of luck and to the film's lasting benefit. With his Irish everyman looks and with a voice so strong that it can raise the rafters, he brings a complete authenticity to the role that lifts the film into another realm, one that matches the soaring beauty of the music.

Hansard's strong performance is matched by the film's other breakout star, Marketa Irglova, 27, the Czech-born singer and songwriter who recognizes his talent and enhances it with her own. Each day they meet on Grafton Street, and an achingly tender relationship forms between them.

Perhaps it's because they are not professional actors with a suitcase full of theatrical tricks that Hansard and Irglova make such a winning couple on the big screen. But that's not to suggest they give unconvincing performances - on the contrary, as professional musicians, their genuine skill and their passion for their work shines through every scene.

"John Carney (the film's director) called me up one day and said he wanted to talk about this script he was writing about a busker," Hansard said during an interview with the Irish Voice.

"I had been a busker In Dublin from the age of 13 onward. He wanted to see if I could add a few ideas to the script. I told him about a lot of incidental stuff that had happened to me - a typical day in the life of a street musician, you know?

"Like when a drunken guy comes up and tries to steal my guitar case. Or when the chanting Hare Krishnas are drowning me out. Or when the passer-bys are asking me to sing Aslan songs. Those were all straight from life. So John gave me the script and asked me to think about writing songs for it. I was delighted when he told me that he really wanted to use all the songs I gave him."

As far as Hansard was concerned, he thought that his involvement in the film would end with his submitting the songs for it.

"At the time the busker was going to be played by Cillian Murphy, and John Carney was looking for an eastern European to play the role of his friend. I suggested Marketa, who I had worked with on my last album, because she fitted the bill. But she had never acted before and she was much younger than the person the director was originally looking for. But he met her and cast her."

A couple of weeks went by, and then out of the blue the director met with Hansard and offered him the part. Hansard was stunned.

"I was a bit freaked out," he says, laughing. "I'm not an actor and I wouldn't have any confidence in that area. I really didn't know if I'd be able to act. He spent a long time persuading me.

"He said you play music together, you know each other really well, I've seen you on stage together - all I want to get is the connection between you that you already have."

There was significant overlap between his life and the life of his character in the film; a hardscrabble background making money to get by, applying for bank loans to pay for recording sessions.

Growing up in the notorious high rise, drug-ridden Ballymun flats in the 1980s, Hansard saw close up what fate had in store for some of his neighbors.

"The flats went up the same year I was born," he said. But Hansard showed a particular talent for music which his teacher, Frankie Byrne, encouraged strongly.

"You can't tell me the square root of nine, but you can tell me who played bass on Blond on Blond - so I'm telling you now - leave school today, start your musical career, get a guitar and go to Grafton Street and start making something of this talent you have. So I took his advice and I busked from when I was 13 until I was 18. Then I formed my own band."

Small but important details make the film so memorable. The scene where Hansard's character plays his first professional demo tape for his appreciative da for example, is particularly tender and funny moment.

"But you know we never saw rushes, it was all up to the director. For months after we made it we hadn't a clue what it would turn out like," Hansard recalls.

After Once was made (and before it received the audience award at the prestigious Sundance Film Festival this year) they had the most modest hopes for it. Says Hansard, "We thought if the film does well we'd put it out on DVD and hopefully cover our costs. We never anticipated that it would take off like this.

"Today we were met at the airport by a luxury bus that has Once written all over it. It's completely the other end of the spectrum to what we imagined the film would ever be. Now we're traveling from town to town across the states and showing up at the cinema to answer a few questions. Word of mouth will get people talking about it, you know?"

Marketa, the film's co-star, mentions the unexpected and unscripted moments that added real beauty to the overall action of the film. A completely unplanned scene where she sings a love song coming out of a local corner shop in Dublin was unexpectedly enhanced by the appearance of some local kids on roller skates who followed her at a discreet distance, looking as though they had been choreographed for weeks. It's an extraordinary moment, and one of many in the film.

Other classic moments include the young Czech immigrant lads settling down to watch the Irish soap opera Fair City in order to learn English. This being Dublin, though, they say "how'ya" to the TV screen instead of "hello," just like the characters on the television.

"I really feel that there's a beautiful connection - whether it's friendship or love or whatever you want to call it. There's a longing throughout the whole of the film, a sort of ache really, that carries the whole thing," says Hansard.

The relationship that blossoms between the two leads is one of the most authentically Irish courtships ever committed to celluloid. All of the halts and hesitations of an awkward - but heartfelt - exchange are on display, making you laugh and touching your heart simultaneously.

Says Irglova, "It's about two people meeting for a week and then parting again. Two paths connect and go along together for a while. We all meet as strangers and the process of getting to know each other is a magical thing."

But don't get the impression this is some kind of sugar coated, insubstantial work. "It's a little love letter to Dublin, but in all its grimy glory," says director Carney.

"And people really seem to connect to it for that. There's no tricks, it's a straightforward story. It was completely amazing that we won the audience favorite at Sundance. We never expected it to take off like this and now that it has we want as many people as we can to see it."

Made on a shoestring budget, with a cast of non-professional actors playing their own music, somehow each of Once's elements came together to make it easily the most satisfying rock musical since Purple Rain.

(Once, produced by Fox Searchlight, opens wide on May 18.)