Sir Christopher Lee fell over a cable and injured his back during production. On the plus side, he was also made a Knight while working on this movie.
This was Christopher Lee's first Hammer film since To the Devil a Daughter (1976) 35 years earlier. It was also his final Hammer film before his death on June 7, 2015 at the age of 93.
Director Antti J. Jokinen told in an interview for Finnish television on June 19, 2010 that Jessica Alba was at first attached to play the role which eventually went to Hilary Swank. Jokinen also told that at one point, Maggie Gyllenhaal was attached to the role.
Shot over a period of thirty days.
The main plot is almost identical to a Spanish movie released on the same year : Sleep Tight (2011).