- For a graphic sex scene, Natalie Portman and Mila Kunis, who are friends in real life (Portman suggested Kunis for the role of her rival, Lily) suggested that a couple of drinks would help break the ice. A bottle of tequila was procured for the occasion, and though a day and a half was blocked for the sequence, Darren Aronofsky, feeling guilty, took a half day away and moved on.
- Blake Lively auditioned for the role of Lilly.
- Vincent Cassel has compared his character to George Balanchine, who co-founded New York City Ballet. The actor said Balanchine was "a control freak, a true artist using sexuality to direct his dancers".
- Meryl Streep was considered to play Erica, Nina's mother.