Director Darren Aronofsky, whose first film was the Kaballah-themed thriller “Pi,” appears to have an Oscar contender on his hands with “Black Swan,” a ballet-themed psychological thriller.

Israeli-American actress Natalie Portman heads up a mostly Jewish American cast that includes Winona Ryder, Barbara Hershey and Ukrainian-born Mila Kunis. Portman plays repressed perfectionist ballerina Nina Sayers, who has been selected for her first prima ballerina role in “Swan Lake.” She replaces the New York troupe’s reigning – and aging – star, played by Ryder.

When artistic director Thomas Leroy (French actor Vincent Cassel) taps Nina to star in “Swan Lake,” he does so with reservations. He knows she is perfect for the innocent White Swan part of the role, but he has concerns whether she can pull off the evil twin Black Swan. Meanwhile, the troupe’s vivacious newcomer Lily (Kunis), who is well-suited for the Black Swan role, waits in the wings.

“Black Swan” is a mad, terrifying thriller, an astounding tour-de-force of startling images and remarkable scenes, as much horror movie as ballet film. It has electrified audiences at Sundance and other film festivals, including the recently concluded St. Louis International Film Festival. The film’s emotional power and creative artistry has been the spark that has generated that Oscar buzz.

Anyone expecting a sweet, pretty story with lots of gorgeous dance sequences is in for a shock. This powerful psychological thriller gives us the drama of a struggle behind the scenes, the blood-and-sweat side of dance. Rather than ballerinas gracefully pirouetting, we see their gnarled feet. Scenes take place in stark dressing rooms and dank hallways with cinder-block walls. Most dance scenes are bits of rehearsals and choreographers working out moves. Only at the end do we see a more fully costumed performance.

There are disturbing, even shocking, scenes of violence and sexuality. The story is wildly dramatic, even verging on melodramatic as it reveals an intense look inside a mind coming unhinged. Few films that have done as well capturing a character’s inner life.

To help the shy, repressed young dancer find her inner Black Swan, the artistic director encourages Nina to explore her own sexuality, perhaps with him. Yet Nina, who lives only to dance, shows an unexpected inner-strength. Still, the suggestion opens the door to an unsettling flood of emotions and desires. Soon, everything in Nina’s life becomes unbalanced, as her own reality and fantasies begin to compete with each other.

While dance fans may be disappointed, the thriller delivers in other ways, particularly in the performances. Portman is a virtual shoo-in for an Oscar nomination; she delivers a riveting turn as a seemingly fragile dancer driven to succeed at all costs. She handles the ballet scenes well enough (she reportedly did 90 percent of her own dancing), although her most memorable work comes from the drama and the way she crafts an unforgettable character.

Hershey is likely to be another contender for awards as she chillingly portrays Nina’s smothering, infantilizing mother, who wraps her adult daughter in world of little girl pink. There is not a weak link in this cast, with excellent work by Ryder in a small role as the outraged aging star, Cassels as the oily, seductive but hard-driving artistic director and Kunis as the outgoing, sly new dancer.

Visually the film is astonishing with Aronofsky displaying his remarkable talent for creating nightmare-like sequences. He masterfully steers the story into a kind of cinematic purgatory, blurring the lines so that we as an audience can no longer tell truth from fiction.

Far different than Aronofsky’s “The Wrestler,” “Black Swan” is a film of disturbing contradictions, a visual stunner and an acting masterpiece juxtaposed in a wildly bizarre story. Whether you love it or leave the theater feeling uncomfortably off-kilter, “Black Swan” is certainly a must-see film of the season.

Black Swan

Rated: R for sexual content, disturbing images

Running time: 1:43

opens: Friday, Dec. 10