"About a Boy"

Marcus isn't immediately lovable: He's as weird and annoying to us as he is to Will, with his assertively all-wrong clothes and his tendency to blurt out the lyrics of soppy '70s songs at inappropriate times. But as Marcus is written (the screen adaptation of Hornby's book is by Peter Hedges) and, even more important, as Hoult plays him, you can't help warming to him.

Marcus' walk, a kind of flat-footed shuffle in which his legs move independently from his rigid torso, at first represents everything about him that's closed off and fearful: By the movie's end, you see it as something different, a natural trait that somehow matches how open and funny and free this kid is. Hoult, with his devilishly unkempt eyebrows and cherubically too-red lips, plays one of those pre-teens who still looks too much like his mother's little boy, and your heart goes out to him -- Hoult doesn't try to grab it from you, as so many child actors do.

Collette, as Fiona, has an even tougher job: Here in the early 2000s, we all recognize that it's perfectly acceptable to laugh at hippies who just can't let go of their security ponchos. Collette actually invites us to; indeed, how can we avoid it, when Fiona shows up for a lunch date with Will in a hairy monstrosity of a sweater that Will later characterizes as a "Yeti costume"?

But Collette also pulls off the more difficult feat of making us feel something for her every step of the way. Fiona is suicidal, but even though we're aware of her pain, we also see how much it hurts Marcus. ("I feel better now," she says simply, beaming calmly at him after she returns from a stay at a mental hospital, as if his loneliness and confusion were mere accessories to her own smoothed-over feelings.) Collette forces us to acknowledge both Fiona's suffering and her selfishness, a tricky line to walk.

She bounces brilliantly off Grant's Will, whose annoyance with her boils into frustration and then full-blown rage, when he confronts her with the ways in which she's "made" Marcus so weird. "You daft fucking hippie!" he hurls at her, and the line is as funny as it is cruel and weirdly poignant. Grant, who used to hide far too coyly behind his public-schoolboy stammer and floppy forelock, has turned into a marvelously unself-conscious actor. He's best when he's playing a bit of a bastard: The evil glimmer in his eyes when he spied Renée Zellweger's giant granny underpants in "Bridget Jones's Diary" was one of the sexiest things I've seen at the movies in years.

Grant's also an incredibly game actor: He gives it the full throttle, in his inimitably understated way, when he explains to two of his sunshiney, new-parent friends that he can't possibly be their infant's godfather because he'll only be trying to put the make on her when she turns 18. It's a hilarious moment, but even more remarkable is the way Grant's resolute orneriness meshes with the person he becomes later in the movie.

When Will notices that Marcus is wearing the dorkiest shoes on planet Earth, he buys him cool new trainers -- Will is grimly determined that the shoes will be what helps this kid through the roughest years of his life, and in a roundabout way, he's right. Grant is wonderful here because he recognizes that a character can soften without turning into a marshmallow. He's also, I have to note, aging beautifully: He has never looked as handsome as he does here. Those few inklings of crow's feet are the best thing that could have happened to his impishly good-looking face.

Every performance in "About a Boy" moves naturally and beautifully in concert with the others. It's a movie that works on every level, starting at its very core. It's the movie the Weitzes were destined to make. They aren't known as subtle directors, although they should be: "American Pie," at first written off as a shallow teen gross-out comedy, has actually found an audience that sees its larger value; for one thing, no teen movie since "Fast Times at Ridgemont High" has shown so much sensitivity toward teenage girls in the face of boys' sexual cloddishness. The Weitzes' second feature, "Down to Earth," didn't resonate as clearly but was nonetheless wrongly overlooked: It's a sweet-natured and well-made entertainment.

But neither picture comes together as wholly as "About a Boy." Its apparent lightness is actually many-layered: The Weitzes are masters at playing two (or, more often, many) emotions off one another at once. When we see Fiona and Marcus gathered round their tinkly home piano, belting out a rousing and stupendously earnest rendition of "Killing Me Softly," we wince, just as Will does. Then, just as it does with Will, our vague amusement at the ridiculousness of it all transmutes into something like horror. And yet, even as we're howling with laughter at them, it's impossible to feel derision -- their belief in the power of this lousy song transcends its innate crappiness, and we see them, and the bond between them, as something inherently wonderful despite its corny trappings.

That's a pretty subtle thing for two directors, best known for a movie in which a teenager humps a piece of pastry, to pull off. But then, "About a Boy" is all about the process of becoming something that no one, least of all yourself, ever thought you could be. The Weitzes have topped themselves, and their movie is an invitation to us to tap the better parts of our nature, without resorting to cheap self-congratulation. The not-so-secret message of "About a Boy" is that people are bastards. And bastards are so much easier to love than saints.

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