Black Swan, Darren Aronofsky’s psychological thriller, is as captivating as it is unsettling; equal parts compelling viewing and terrifying discomfort. Unfolding within the physically and mentally demanding world of professional ballet, it carries echoes of the director’s previous effort – 2008’s excellent The Wrestler – with its gritty portrayal of the pressures endured by professional athletes, and the emotional cost of dedicating one’s life to an art.

The film opens with Nina (Natalie Portman), a fragile young dancer sharing a small apartment with her mother, both of whose lives seem entirely dedicated to Nina’s career as a ballet dancer. Almost immediately, we are aware that the relationship is unhealthy, and the hugely impressive Barbara Hershey is frighteningly believable as an obsessive, over-bearing parent living vicariously through her daughter.  Apart from her disturbingly child-like existence at home, Nina also finds herself auditioning for the lead role in her company’s new production - Tchaikovsky’s Swan Lake. The role entails playing two characters on opposite ends of the personality spectrum; the chaste and innocent White Swan, and her evil twin the Black Swan. The company’s director, Thomas (Vincent Cassel), sees Nina – with her perfect technique and dedication – as being perfect to play the former, but too inhibited to adequately portray the latter. Thomas has a reputation for bedding his prima ballerinas, and his former star and lover, Beth (Winona Ryder), does not take kindly to being forcibly replaced by Nina, onstage or otherwise. Further complicating matters is the arrival of Lily (Mila Kunis), a new dancer that is everything that Nina is not: confident, brash, and liberated. Lily tries to befriend Nina with suspicious enthusiasm, but, just as twins tend to be, she becomes both a friend and a rival.

On the surface, Black Swan explores familiar themes: conflict between good and evil, life imitating art, the dangers of blind ambition, and the juxtaposition of a virginal, naïve protagonist against her worldly, hyper-sexual polar opposite. Even the ballet from which the film takes its name is familiar to most with a passing interest in such things. What elevates this film beyond most others in the genre, however, is the setting. As the film progresses, we come to realize that most of what we see takes place in Nina’s mind. Thus, Black Swan is less about ballet than it is about one fragile young woman’s debilitating neuroses. Aronofsky has shown himself to be quite adept at unsettling his audience by decentering reality, and Black Swan does this to remarkable effect. While the first act seemingly sets the stage for a melodrama about obsession and sexual competition, the second and third are all about Nina’s descent into mental disintegration, and a look inside the mind of a possible paranoid schizophrenic. At no point can we again separate the real from the imagined.

Just as her character is faced with the daunting task of convincingly portraying both the White and Black Swans, so is Portman challenged with fulfilling a role that requires her to successfully embody this duality. Fortunately for us, she is magnificent; equally convincing as the fragile, sheepish embodiment of the White Swan as the more sinister, lustful Black twin. Already the object of many a nerd’s fantasies (guilty as charged), Portman has previously shown an impressive acting range perhaps not immediately apparent in the flat performances delivered in the Star Wars films that first catapulted her to stardom. In this film though, she delivers an unforgettable tour de force, with such subtlety and emotional authenticity as to make her a heavy favourite at this month’s Academy Awards. Black Swan is a fine film, but Portman’s performance alone is worth the price of admission.