By this point, Michael Fassbender has become so entrenched as one of The Great Actors of His Generation that it's kind of weird to think of how recently he wasn't. Like, three years ago. Oh, there was 300, but nobody watching that really had much to say about the acting, and certainly nobody noticed the one German-born guy with an English accent who hadn't been in a movie before, and Band of Brothers had such a big cast, how were we supposed to notice him! Anyway, that changed with a thunderous crackle when conceptual artist Steve McQueen* made his cinema debut with Hunger, in which Fassbender played IRA soldier Bobby Sands and was hugely goddamn amazing, and it was then that the lucky people who saw the movie realised that we had here A Talent To Follow. It was, in all that time since, the actor's best performance, and now it has a little brother, for Fassbender and McQueen have teamed up again to make Shame, a great sophomore effort to go along with one of the best debuts of the last ten years, and maybe the best work of Fassbender's short but intense career.

One of the things that makes the director/actor collaboration so incredible in both cases is Fassbender's absolute commitment to giving McQueen his physical body as a palette: in Hunger, by playing a grossly emaciated hunger striker, and in Shame by parading around naked. This sounds flippant, and it isn't: if you have been paying attention at all, you probably know that Shame is the latest film to win for itself the notorious and rare NC-17 rating, on account of having a lot of sex scenes that leave powerfully little to the imagination, as well as full frontal nudity from both Fassbender and Carey Mulligan, who plays his sister. The prurient might react with a hearty "alright!", and would be rather devastated to find that Shame, like most movies with borderline-pornographic sex scenes, is rancidly anti-erotic; but the prurient have a point, which is that any time a celebrity appears naked in a movie or otherwise, a whole lot of people are going to be interested in seeing it, all the more so when that person is as excellently attractive as Fassbender and Mulligan are. McQueen is absolutely aware that he has naked celebrities in his movie; he counts on it. Much of the disquieting effect of Shame comes from the weirdness that comes from watching two up-and-coming stars wearing nothing at all in such a bland way (the first time we see Lil' Fassy, it's in a wide shot that consists of nothing but the actor wandering around a corner in a glamorous New York apartment), not leering and really not leading us to have any particular feeling about it whatsoever. The suddenness and casualness of the nudity in the movie knocks us out of orbit; it makes watching Shame a very weird and uncomfortable experience, and that is exactly right.

The film, which McQueen co-wrote with Abi Morgan, introduces us to a man named Brandon Sullivan (Fassbender), a well-off midlevel executive at some financial concern or another, who lacks any sort of personality besides the one thing: a voracious appetite for sex, especially degrading, unsavory sex (in one of the film's many piercing moments, he has to hire a prostitute after he's unable to maintain an erection in the presence of a woman who seems to enjoy him in a mature, adult way). Unpacking all the different shades of meaning in the title could be an essay in and of itself, but I'll stick with the obvious one: he needs to feel shame to get turned on, and apparently every detail of his life is arranged to facilitate that.

Until one day, his sister, Cissy (Mulligan), shows up out of the blue from Los Angeles, looking to crash at his place while she has a gig singing at a nightclub. This upsets his whole precious little life and forces him to confront on a daily, almost hourly basis, his inability to feel feelings for other people, even the only family he has left and the only person he's ever been close to; and he feels shame about this, too, but it's the kind of shame that turns into a snarling, acidic hate aimed right at his sister.

Deep in its heart of hearts, underneath all of the button-pushing sexuality and nudity and emotional savagery, Shame is a tremendously conservative movie, whose moral boils down to the simple proposition that having an emotional connection with other people is better than anonymously fucking them. Putting Shame squarely in the tradition of hyper-sexual movies that are essentially sex-negative, although surely Brandon is such a special case that McQueen can't expect us to take him as an Everyman, whose life lessons are meant to be duly taken down by every one of us. There is nothing remotely that programmatic here, just a closely-observed character study that makes extraordinary use of its leading man - the film is purposefully underwritten, and shot in a series of detached long takes that frequently place us as voyeurs craning in to watch the characters, but never share their point of view, which means that for us to understand Brandon at all, it falls to Fassbender's drained expressions and physical carriage. This is what happens when you have complete trust between filmmaker and star; it is the promise of Hunger paid of in spades. McQueen has not given Fassbender a showcase, so much as he demands that Fassbender give every inch of himself to the movie because otherwise the movie could not work.

There's more to the movie than just one performance: Mulligan has to carry a lot of the emotional weight all by herself (it's the best work of her career, too), and even the film is about 90% a two-hander between these leads, or Fassbender solo, there are a few excellent supporting turns, especially Nicole Beharie as a co-worker Brandon takes a shine to, and then subjects to one of the most awkward first dates in recent cinema history, the kind of "where have you been all my life?" performance that should, in a perfect world, set her on a Fassbender/Mulligan-like path to instant ubiquity, but it is not a perfect world, so we must wait and see.

Heck, there's more to the movie than just the actors, though McQueen is not so invested in technique as he was in Hunger (there's nothing remotely comparable to that film's show-stopping 17-minute one-take interrogation in a static two-shot), though the few times he picks up the droopy pace to give the film a blast of energy are taut and intelligent filmmaking at its best. It is restrained filmmaking, but restraint is best for this particular character study, and I cannot imagine a better iteration of this story than the one we've got.

There's only one problem, really, which is that Shame, like Hunger, feels a bit too pridefully theoretical: fleshiness and messy, unpolished sex and all, it's a touch clinical and inhuman (and too self-aware with its deliberately vague ending). Less so than its predecessor - being about sex rather than about politics will do that - but there is a huge difference between being struck dumb by the severity of Brandon's sexual addiction and being struck dumb by the bravery and excellence of Michael Fassbender in depicting that addiction. It's still compelling and absolutely essential adult cinema - that is, cinema for thinking adults to ponder and discuss and reflect upon (in fact, I think it to be one of the few films in 2011 that I'd call essential viewing in those terms) - but there's something alienating and off-putting right barely on the edges, and not in the good way.

*Who owes his parents a lot for that name.