• 1. Justin Timberlake lost 15-17 pounds for his role as Sean Parker. He thought looking thinner would make him look younger.

  • 2. In an interview with Diane Sawyer, Mark Zuckerberg revealed that Jesse Eisenberg’s cousin, Eric Fisher, worked at Facebook.

  • 3. In preparation for his role as Mark Zuckerberg, Jesse Eisenberg registered with Facebook two weeks before he began work on the movie. When the production wrapped, he canceled his account.

  • 4. Every shirt and fleece that Jesse Eisenberg wears in the film is something that the real Mark Zuckerberg has worn.

  • 5. After casting, David Fincher forbade principal actors from meeting their real-life counterparts until filming was completed. Justin Timberlake was the only actor who met his real-life counterpart, Sean Parker, during filming.

    Via.

  • 6. The original banner at the top of Facebook.com included a stylized portrait of a young Al Pacino. It was designed by Andrew McCollum, a friend of Mark Zuckerberg. The banner used on the website in the film uses a portrait of Jesse Eisenberg.

  • 7. The Social Network is the first PG-13 rated film to feature two separate, unrepeated instances of the word fuck.

  • 8. Natalie Portman, a Harvard student during the time of Facebook’s creation, gave writer Aaron Sorkin some insider information about how things really happened on campus. Sorkin thanked her by referencing her in a scene.

  • 9. The opening breakup scene with Jesse Eisenberg and Rooney Mara took 99 takes.

  • 10. In a scene where Mark Zuckerberg is taking art images from a Facebook profile to fulfill an Art History class requirement, the Facebook profile he is viewing is that of Tyler Durden, a character from another film directed by David Fincher, Fight Club.

  • 11. Mark Zuckerberg originally planned on never seeing the movie.

  • 12. Jesse Eisenberg and Andrew Garfield became good friends during filming. According to Eisenberg, the dramatic rivalry between their characters was hard for the two because it affected them emotionally.