Both fascinatingly theatrical and thrillingly cinematic, a picture that's lingered on our minds more than we expected.

If it doesn't ultimately engage your heart as it might, Anna Karenina is period drama at its most exciting, intoxicating and modern. Spellbinding.

Knightley embodies Anna as a girlish woman who has never felt erotic love; once smitten, she is raised to heavenly ecstasy before tumbling into the abyss of shame. It's a nervy performance, acutely attuned to the volcanic changes a naive creature must enjoy and endure on her first leap into mad passion. She helps make Anna Karenina an operatic romance worth singing about.

The results are generally refreshing. Much of the film takes place inside a theatre, as if to suggest the shenanigans of the Saint Petersburg aristocracy were a form of public entertainment.

Setting most of the action in a mocked-up theater emphasizes the performance aspects of the characters' behavior, a strategy enhanced by lead thesp Keira Knightley's willingness to let her neurotic Anna appear less sympathetic than in previous incarnations.