In the middle of March 2009, Liam Neeson interrupted filming his scenes, in order to visit his wife Natasha Richardson in the hospital, after she had a skiing accident. The brain injury she received from this accident, lead to her death a few days later. Just few days after her death, Neeson voluntarily returned to the set, and completed his performance. The filmmakers changed the script accordingly, and Neeson completed his performance in two days.
This film was solely financed by the French company StudioCanal, which had entirely recouped this film's budget via international pre-sales (before this film's first festival screening).
Screenwriter Erin Cressida Wilson wrote the part of Catherine, specifically with Julianne Moore in mind.
Executive Producer Jason Reitman helped persuade Amanda Seyfried to star in this film.
Mirrors are frequently featured in the film, and when they are, there is usually more than one mirror in the same shot. A prime example would be the scene in the hotel room between Chloe and Catherine.
Several months after this film's DVD/Blu-ray release, Atom Egoyan announced to The Toronto Star that this film had became his biggest moneymaker ever.
Chloe's last name is Sweeney. It is mentioned only once throughout the entire film, when she introduces herself to Michael at Catherine's office.
Erin Cressida Wilson originally located her screenplay in her hometown of San Francisco. When Atom Egoyan came on board, she changed the location to Toronto.
This marks one of the very few times that Atom Egoyan did not cast his wife 'Arsinee Khanjian' in a role.