Other Mommy: Jessica Chastain’s New Horror Movie Is Now in Theaters—Cast, Story and Book Behind It

Other Mommy, the new horror film starring Jessica Chastain, opened wide in U.S. theaters on October 9, 2026. Chastain plays two roles: Bela’s mother and a threatening entity that looks like her. Directed by Rob Savage, the film adapts Josh Malerman’s novel Incidents Around the House.

What is Other Mommy about?

Bela is a young girl whose home no longer feels safe. A presence she calls “Other Mommy” appears in the house looking uncannily like her mother and becomes increasingly threatening to the family. The resemblance puts a disturbing question at the center of the story: how can Bela trust the person who should make her feel safest when something else can wear her face?

Chastain’s dual role makes that threat more than a stranger-in-the-house premise. She portrays both Bela’s mother and the entity imitating her, while Jay Duplass plays Bela’s father. Arabella Olivia Clark plays Bela. The film also features Dichen Lachman, Arian Moayed and Karen Allen.

Is Other Mommy based on a book?

Yes. Other Mommy is based on Malerman’s 2024 horror novel Incidents Around the House. The book follows Bela and her family as the entity grows more persistent. Readers may recognize Malerman as the author of Bird Box, another horror novel adapted for the screen.

The film takes its title from Bela’s name for the presence rather than using the novel’s title. Nathan Elston wrote the screenplay, and Savage directed. The project comes from Blumhouse and Atomic Monster, with James Wan among its producers. Savage previously directed the horror films Host and The Boogeyman.

Where can you watch Other Mommy?

Other Mommy is playing in U.S. theaters following its October 9 wide release. Moviegoers can check local theater listings for showtimes; the theatrical opening does not establish when the film might become available to rent or stream at home.

The film runs 1 hour and 33 minutes. It is rated R for some bloody violence and language, making the rating worth checking before planning a family outing. Although the story centers on a child, Other Mommy is an adult-oriented horror release.

For viewers deciding whether to see it, the essential distinction is straightforward: this is a supernatural story about a girl confronted by a copy of her mother, not a new film titled Incidents Around the House. That is the name of the book behind Chastain’s latest theatrical horror role.