Trivia: Writer/Director Parker Finn has a cameo as the photographer during Skye's photo shoot.
Trivia: The restaurant near the bookstore where Charlie works is called the Double Deuce. Double Deuce was the name of the Road House in the 1989 film version.
Trivia: Michael Bond, the author of the Paddington book series, appears in this movie as a stamp.
Trivia: Star Dwayne Johnson reportedly pushed to have the film be shown in IMAX theatres after seeing Christopher Nolan's film "Oppenheimer" in IMAX. Johnson reasoned that "Red One" in IMAX would be "game over," and would make the film a huge hit. The film ended up bombing, and Johnson's comments were widely mocked online, with some labelling him "delusional" for trying to compare the releases of "Red One" and "Oppenheimer." (Though in his defence, he never directly compared the films themselves.)
Trivia: The first time Maika Monroe saw Nicolas Cage in make-up as Longlegs, her heart rate jumped up to over 170 bpm, around 100 above her resting heart rate.
Trivia: Chip, who plays the role of Alfie (Ellie's cat), is the pet cat of Claudia Schiffer, the wife of the film's director, Matthew Vaughn.
Trivia: Willem Dafoe previously played Max Schreck (and by extension, Count Orlok) in Shadow of the Vampire, which is a fictionalized telling of the filming of the 1922 Nosferatu film.
Trivia: Near the beginning of the movie, as the SWAT vehicles are approaching, a billboard is visible in the background advertising the movie "The Watchers", which was directed by M. Night Shyamalan's daughter, Ishana.