LONDON — Adam Wingard’s killer thriller “The Guest,” starring “Downton Abbey” star Dan Stevens and rising thesp Maika Monroe (“The Bling Ring,” “It Follows”), is set to open Film4 FrightFest in London.

The film, written by Simon Barrett (“You’re Next,” “A Horrible Way To Die”), also stars Sheila Kelley (“Matchstick Men”), Leland Orser (“Taken”) and Lance Reddick (“The Wire”).

Pic, which is an homage to 1980s action movies, opens with the Peterson family struggling to cope with the death of their son, Caleb, in the Afghanistan War. They find some solace when an unexpected visitor knocks on their door, claiming to be Caleb’s former comrade.

Siblings Anna and Luke are at first reluctant to accept David’s presence, but he soon wins them over. Then a sinister chain of events causes Anna to question whether David is who he claims to be.

Alan Jones, co-director of FrightFest, said: “Film4FrightFest has a grand tradition of always opening its banner August event with a forward-looking and directional attraction. So we couldn’t be more delighted to showcase Adam Wingard’s dazzling horror thriller ‘The Guest’ to put the stamp of approval on our move to the Vue cinema in Leicester Square.”

Wingard said: “FrightFest movie-goers are some of the most diehard genre enthusiasts in the world. Naturally I am delighted that ‘The Guest’ will be opening this year’s festival.”

“The Guest” is being distributed in the U.K. by Icon Film Distribution.

The fest also announced that Claudio Simonetti’s Goblin will be performing live scores for George Romero’s “Dawn of the Dead” and Dario Argento’s “Suspiria.”

The fest runs Aug. 21-25.