Films about the the recording of music can often struggle to capture the act of creation in a believable fashion. Some can capture that moment of inspiration and the coming together of disperate elements to fuse together in a perfect harmony: The Buddy Holly Story, for instance, or more the more recent Johnny Cash biopic Walk the Line spring instantly to mind. By contrast, it can be rather hammily assembled; the creation of ‘Light My Fire’ in Oliver Stone’s The Doors laboured the classic organ riff’s inception to the point of smelling rather cheese-like. Once, thankfully, is the former, and it is to director John Carney’s credit that the film manages to walk the tightrope between reality and musical fantasy so effectively.

Firstly, the key to the film’s believability is the fact that the songs are clearly being performed by the films two leads and not by some fake shemps lurking off camera. If one reimagines the film as a Hollywood romantic comedy starring, say, Meg Ryan, then the film with the same plot would be sub-TV-movie fodder. What we have here, though, is two endearingly honest performances by real-life musical collaborators Glen Hansard and Marketa Irglova, giving a window of insight into the way their songs are created, re-shaped and recorded. While the songs themselves are pleasant enough, they are perhaps not strong enough to stand out if, for instance, one overheard them on the radio; what gives the presence of the songs its magic is the performance aspect, as so often can be proved, a live performance of an ordinary song can make it truly extraordinary.

Of course, this is not a documentary about two recording musicians, so we have a fairly standard boy-meets-girl narrative with the usual mis-steps and twists and will-they-won’t-they moments. It is pleasing to note that the film functions on this level too; I don’t invoke the name of Richard Linklater in vain, but there is an easy charm and wide-eyed optimism about Once which is reminiscent of Linklater’s Before Sunrise, for my money the Citizen Kane of modern ‘romantic’ films (I add the inverted commas because to reduce said film to a mere genre label does it no justice whatsoever).

But back to the music; possibly the one thing about the film that stayed with me most was its understanding of the role of music. The male protagonist, ‘Guy’, is not some wannabe X-Factor muppet intent on fame at any cost; he is planning to move to London primarily to win back his ex-girlfriend, the girl whom he seems to write and sing most of his songs about. His creative impulse is both one of catharsis and a deep longing; like Alvy Singer in Annie Hall, it stems from the need to make things in art perfect because its so difficult in real life. Similarly with the ‘Girl’ in the film: it transpires that she is married, but her relationship is far from perfect, and the music she makes is both reflects this, and signals her desire to heal those emotional wounds.

We also see the flipside of the coin: the way the songs affect the listener. In several poignant scenes we see how music is an escape for these characters; ‘Girl’ walks home late at night from the corner shop listening to a borrowed CD player, the music transporting her away from her mundane surroundings to what seems like another world. Similarly, in an earlier scene, a simple duet between our two protagonists on the floor of a piano shop whisks us temporarily away from a drab Dublin high street and into the high heavens. A great record can take a listener away to such places, if they are willing to go there; this wonderful film made me want to go wherever it was taking me.