Dutch thriller "APP", about a mysterious personal assistant application that takes over mobile phones, requires viewers for the first time to look at their smartphones in the cinema to view extra footage.
In the film, nefarious app "Iris" -- which happens to be the name of the personal assistant found on Apple's iPhone, Siri, written backwards -- takes control of the smartphone of the heroine, 21-year-old psychology student Anna.
"We wanted to make a film about mobile phones, about how the technology can turn on us," Edvard van 't Wout of production company 2CFilm told AFP at a press viewing on Wednesday.
Van 't Wout says this is the first time that such "second screen" technology has been used in a cinema.
The film begins with a parody of the typical request from cinemas and asks viewers to "kindly to turn on their mobile phones".
Similar technology has however been used in films to be viewed at home.
The idea behind "APP" is simple: viewers download application software to their smartphones or tablets and activate it in the cinema.
Film content within the app is activated at specific points in the film thanks to inaudible signals in the soundtrack.
Viewers see silent plot elements appear on their smartphones: text messages between the film's heroine and her best friend, a newspaper story about a suicide on the big screen or what the heroine herself is seeing on her phone.
The thriller, rated for 12-year-olds and over, can be watched without a second screen, but "you lose out," director Bobby Boermans told AFP.
Boermans says creating the film was a bit like "having to write two scripts."
Some shots in the film were deliberately lengthened in editing to allow viewers time to digest the small-screen information before turning back to the big screen.
The film is due out in the Netherlands on April 4 and is set to be dubbed into English for foreign release.