Trivia

André Øvredal said that Olwen Catherine Kelly had the most difficult role in the film, and he credited her with making everyone else comfortable on the set.

One of the reasons Olwen Catherine Kelly was selected for her role as Jane Doe was her knowledge of yoga, which helped her control her body and breathing.

Although there are some prosthetics used, the role of the naked corpse, for the most part was played by actress Olwen Catherine Kelly. André Øvredal felt that it was necessary to have a live actress for the part to help connect the audience on a human level. On some level the decision was also a practical one as Øvredal believes that doing some of the close up scenes with a prosthetic would've been impossible.

The Norwegian director André Øvredal was inspired to do a horror movie after attending a screening of The Conjuring (2013). He immediately called his agent and told them that they should try and find a good horror script for him. A month later they showed him this script and he was immediately interested.

Olwen Kelly spent around eight hours a day for five weeks lying naked on an autopsy table. Before filming, she said she spent a lot of time thinking "how am I going to be nude, and still, in what will probably be a room full of men?" Her background as a model helped her cope. During an early modeling job after moving to London, she posed totally naked except for a pair of shoes in a room full of people.