Adam Pearson, who plays the disfigured man who is lured into the vehicle, broke his leg when he was struck by a cab on his way to audition for his role. Director Jonathan Glazer auditioned him the next day at the hospital and gave him the job.
Close to the end, one of the motorcycle riders overlooks a valley shrouded in fog. The composition of the image and the pose of the rider mimics Caspar David Friedrichs' 1818 oil painting "Wanderer Above the Sea of Fog".
The film took nearly ten years to be made, and one of the early drafts of the scripts included a Scottish married couple who were revealed to be aliens in disguise. Brad Pitt was, at the time, cast as one half of the couple.
A paparazzi still of Scarlett Johansson, in character, falling down became a wildly popular Internet meme in which users would Photoshop Johansson into various situations. As the scene was shot with hidden cameras, it was not until the movie's release that it was revealed the fall was intentional.
Jonathan Glazer did not want to use make-up for the man with neurofibromatosis. Adam Pearson was cast after the production team contacted Changing Faces, a charity supporting people with facial disfigurement. His ideas about how Scarlett Johansson's character could seduce his character were added to the script.
One of the locations where this film was shot was in the Robert Street area of Port Glasgow (where the second victim is lured). Filming had to be delayed for a number of days as there was a real-life murder in the next street prior to filming and the police had cordoned the area off.
The nightclub that Scarlett Johansson gets pulled into is Club Earth in Livingston, West Lothian. Although the exterior shots and many of the interior shots are of the actual club, her escape route and scene in the toilet corridor seem to have been filmed elsewhere.
The scene where Scarlett Johansson enters the stone hut for shelter was filmed on the eastern shores of Loch Lomond over two days. The cast and crew had to be taken by boat from Tarbet to the set, as there is no road access. The only access is a footpath known as the West Highland Way.
The trivia items below may give away important plot points.
One theory suggests that The Female is actually a Selkie instead of an alien. Selkies are mythological creatures found in Scottish, Irish and Icelandic folk lore. They are said to live as seals in the sea but shed their skin to become human on land. Selkies are described as being very beautiful in their human form and therefore having great seductive powers.
Adam Pearson (The disfigured man) was interviewed on the Australian morning talk show "Studio 10" about the film and had stated the scene where he runs naked through a field in Scotland was filmed at 3:00 am and that it was extremely cold.