Keira Knightley who was 17, lived on her own for the first time while filming for three months in Slovakia and Prague. She said her Prague flat was located in the center of the city's red-light district and the actress made friends with a local prostitute, who positioned herself directly under her window every night.
Sam Neill plays the part of Kamarovsky, a part played in Doctor Zhivago (1965) by Rod Steiger. James Mason, who was Neill's acting mentor, was offered the role.
Andrea Corr was originally offered the role of Lara Antipova, but she turned it down because she didn't want to do the nude sex scenes.