They Know

They Know is an upcoming American horror film starring, written, and directed by Bill Hader. The film is based on an original story by Hader and Barry writer Duffy Boudreau. This film mark's Hader's feature directorial debut.

They Know
Directed by	Bill Hader
Written by	Bill Hader
Story by	Bill Hader & Duffy Boudreau
Produced by	Bill Hader Robert Graf Alyssa Donovan
Starring	Bill Hader Linda Cardellini
Production companies	MRC Hanarply
Country	United States
Language	English

Premise

A divorced father (Hader) grows suspicious that a mysterious man dating his ex-wife (Cardellini) is having a strange influence on their daughters (Lang and Mote).

Cast

• Bill Hader
• Linda Cardellini
• Lilou Lang
• Lorelei Olivia Mote

Background

The film is based on an original story that Hader had conceived with longtime collaborator Duffy Boudreau. Hader initially wrote the script, which in an interview Ari Aster described as being "incredibly personal" to Hader, after wrapping the final season of Barry. Hader struggled to find financing due to the "disturbing" and "cynical" nature of the script, and briefly shelved the project. He revealed that he was inspired to return to the project after watching Aster's 2025 film Eddington.

Production

Hader had previously directed 18 episodes of the HBO crime tragicomedy series Barry, which he co-created and starred in.

The film is being financed by MRC. Hader and Robert Graf will serve as producers under the formers "Hanarply" banner, with Alyssa Donovan serving as co-producer.

Production began in Los Angeles on April 13, 2026, where it was announced that Linda Cardellini would be joining the cast as the protagonist's ex-wife. On April 28, 2026, Lilou Lang and Lorelei Olivia Mote were announced to be joining the cast, playing the daughters of protagonist.

External links

• They Know at IMDb