About a Boy (12)

Everything but the girl

Balancing acts: this is the signature predicament of that peculiarly modern male, Homo Hornbiensis. In Fever Pitch a man has to balance the demands of romance and football. In High Fidelity it's the demands of romance and pop music. In About A Boy, the third and latest Nick Hornby novel to be adapted for the screen, it's a balance between romance and, well, the necessity of being the centre of one's own existence. If this last doesn't quite trip off the tongue like the other two, it's actually the most realistic of the obstacles to romance, football and pop music being only symptoms of male self-obsession.

In the case of Will, protagonist of About A Boy, it almost amounts to a philosophical emergency: does he really have a "self" to be obsessed with in the first place? The worry is engagingly expressed in Hugh Grant's performance, which soft-pedals his familiar repertoire of splutter-and-stutter (the accent has moved a couple of stalls downmarket) but gains character with every new scene he plays. Will is a type formerly known as a "swinging bachelor", a 38-year-old without a job, a relationship or, apparently, a care in the world. Rich from the royalties of a one-hit wonder his father wrote years back, he loafs about his huge Clerkenwell flat or razzes around the streets in his sports car, a living rebuke to Donne's famous line, "No man is an island". (This playboy life didn't seem so bad to me, but then, I'm a very shallow person.)

Indeed, so insular is Will's life that the film seems to have forgotten to give him any friends, or at least friends who know him well enough not to ask if he'll stand as godfather to their toddler: there's a good early shot of him holding the infant as if he were an unexploded bomb. Never one for complication, Will discovers that the safest route to hassle-free relationships is the single mum: he can pretend to be a parent without having to shoulder any of the responsibility. So taken is he with this idea that he begins attending local meetings of SPAT (Single Parents Alone Together) in search of some attractive and vulnerable woman who'll just be grateful for the attention.

At first it works like a dream, and his bogus (and conveniently absent) child, "Ned", allows him to shark around an unsuspecting mother (Victoria Smurfit). Then he meets a lonely 12-year-old, Marcus (Nicholas Hoult) and his unhappy mother Fiona (Toni Collette), and his "island" paradise is suddenly and rudely invaded.

The film, written and directed by Chris and Paul Weitz, inverts the approach taken to the previous Hornby adaptation, High Fidelity. Whereas the latter swapped its London setting for America but relied on a British director (Stephen Frears), About A Boy imports its directors from America but stays in London. The Weitz brothers, whose big hit was American Pie, might not seem an obvious choice, but they've managed to give the material a light, amiable swing, oiled further by the hybrid pop stylings of Badly Drawn Boy.

What slightly undermines the film is the same trap Stephen Frears stepped into on High Fidelity. More than plot or theme, "voice" is the key to Hornby's books, the thing which makes that vital communion between writer and reader, and because Hornby's is so distinctive it's natural that a film should try somehow to duplicate it. Unfortunately, voice is not the same thing as voiceover, and at times the Weitzes' script merely recites the novel instead of dramatising it. Not that voiceover should be outlawed completely – Y Tu Mama Tambien, the film of the year so far, uses the device to tell us things we couldn't possibly know from merely watching. And About A Boy gets its biggest laugh during its gravest passage of drama, when Will stumbles on an attempted suicide: "It was horrible, horrible – but driving fast behind the ambulance was fantastic."

There was almost as much cackling when Fiona and Marcus sing a mawkish duet of "Killing Me Softly" at the piano, while Will privately confides to us: "The worst bit was when they closed their eyes." Funny, but it might have been even funnier just to let Hugh Grant's look of frozen politeness make the point. The first 10 minutes, a precis of Will's life, feel cramped because his voiceover is telling us what we can already see. Vital turning points keep being flagged. Gradually Will and Marcus realise that their unlikely friendship is changing their lives – but we could have twigged that without a commentary to prod us. It suggests that the film-makers don't quite trust the audience to "get" it. It's a pity, because the performances are sufficiently nuanced for us not to need the verbal prompts.

Toni Collette and Nicholas Hoult are a good match as mother and son, and Rachel Weisz as another single mum Will falls for is one of the most natural performances she's given. The main reason to see the film, however, is Hugh Grant, who does a fine job of looking deeply into a shallow soul. Grant may never break out of playing toffs and cads, but were he to invest each role with as much thoughtfulness as this he wouldn't have to.

If Will were the sort of man who spent time reading poetry instead of watching Countdown, he might see his worldview endorsed in Larkin's poem "Love" – "How can you be satisfied,/ Putting someone else first/ So that you come off worst?/ My life is for me./ As well ignore gravity". But Grant's skill is to convince us of Will's change of heart as the film goes on: complacent, sneaky, selfish, lustful, embarrassed, disconsolate, fearful and, finally, compassionate and open. In his own way, he's learnt to ignore gravity.