Olga Kurylenko, familiar with Terrence Malick's tendency to cut entire characters out of his movies completely, made him promise that he would keep her in the film.
Roger Ebert's review of this film was the last review he submitted before his death. It was published posthumously.
There was no script that was used during filming. Terrence Malick would give the actors pages of thoughts and independent lines every morning and he would ask them to play the emotions without speaking, just with their body.
Rachel McAdams lied about her horse hair allergy, to get the part.
Tatiana is the only character referred to by name on-screen, all other characters' names are revealed only at the end credits.