Noticeable for those who are fans of Aronofsky's work, the bald guy in the suit on the subway is played by Stanley Herman, who played Uncle Hank from Requiem for a Dream (Aronofskysaid that it's actually the same character) and the bald guy in the suit on the subway (aka the Moustacheless Man) in π.
One of the wealthy attendees of the party is played by Mark Margolis, who Aronofsky fans will recognize as Sol from π, Mr. Rabinowitz from Requiem for a Dream, Father Avila from The Fountain, and Lenny from The Wrestler.
Sebastian Stan has a brief role as Andrew, one of the guys that Lily and Nina meet on their night out together. Lily chooses to go home with the other guy, though, for some baffling reason.
Real-Life Relative: Mr. and Mrs. Stein are played by Abraham and Charlotte Aronofsky - Darren Aronofsky's parents.
Romance on the Set: Natalie Portman and the film's choreographer Benjamin Millepied. They're now married and have a child together. It became Hilarious in Hindsight as Benjamin Millepied is the guy Thomas asks if he would do Nina, Natalie's character. He answers no. Portman, heavily pregnant during her thank you speech at the Golden Globes: "He's the best actor! It's not true! He totally wants to sleep with me!"
What Could Have Been: Summer Glau revealed at Emerald City Comicon 2012, that she had auditioned for a supporting role in this movie, but during the pre-production stages, the character was cut from the story.