Show creator Chris Carter will reunite with its stars David Duchovny and Gillian Anderson, who will reprise the roles of FBI agents Fox Mulder and Dana Scully.
Earlier this week reports revealed that shooting for the film would begin in December in Vancouver, Canada.
The X-Files TV series ran between 1993 and 2002, with the first feature film being released in 1998 and grossing $187 million globally.
Carter will write and produce the film alongside Frank Spotnitz, but the storyline has not been revealed.
So far only two other movies have been confirmed for the same release date - comedy Step Brothers starring Will Ferrell and an untitled film with Ice Cube.