Halloween season has a new nightmare on the way. The Other Mommy Jessica Chastain movie — Blumhouse and Atomic Monster’s psychological horror film Other Mommy — opens exclusively in theaters on October 9, 2026, positioning the Jessica Chastain-led chiller as Universal’s big pre-Halloween swing and the clear favorite in what is shaping up to be a horror-versus-drama box office showdown.
With exactly one week to go until release, the studio dropped the final trailer on September 25, and the reaction from the horror press was immediate. Scream Horror Mag called the footage “pure nightmare fuel,” per its coverage of the trailer launch, while the film’s official synopsis and casting have only added to the buzz: Chastain plays not one but two roles — a mother and the monster wearing her face.
What Is the Other Mommy Jessica Chastain Movie About?
Other Mommy opens exclusively in theaters on October 9, 2026. The film centers on Ursula, played by Jessica Chastain, the mother of an eight-year-old girl named Bela. When Bela begins forming a strange, unsettling bond with a presence inside the family home — an entity masquerading as her mother — the line between parent and predator starts to blur. Chastain’s second role is the entity itself, known as the “Other Mommy,” a terrifying figure who torments the family from within.
The film’s signature hook is a single, skin-crawling question the entity asks the child: “Can I go inside your heart?” It’s a line that horror outlets have seized on since the trailers began circulating, and it captures the film’s core dread — not a jump scare, but an invasion wearing a mother’s face.
The story unfolds largely from Bela’s point of view, a framing that has drawn comparisons to Coraline: an evil doppelganger, a child’s-eye perspective, and a home that stops feeling like home. Flicks.co.uk has described the premise in Coraline-esque terms, and the eight-year-old POV gives the scares a distinctly vulnerable lens.
The Source Material: Josh Malerman’s “Incidents Around the House”
The film is adapted from the New York Times bestselling novel Incidents Around the House by Josh Malerman — the author behind Bird Box, the 2014 novel that became a global Netflix phenomenon. Like Bird Box, Malerman’s novel roots its horror in a confined, domestic setting and a parental fight for a child’s survival, which made it a natural fit for Blumhouse’s brand of high-concept, budget-efficient horror.
The screenplay comes from Nathan Elston, known for his writing on HBO’s Succession, and the film is directed by Rob Savage, the filmmaker behind the lockdown-shot found-footage hit Host (2020) and the Stephen King adaptation The Boogeyman (2023). Savage’s track record with intimate, single-location scares makes him a logical choice for a story that traps its characters inside one haunted house.
Producing is genre heavyweight James Wan, whose Atomic Monster banner joined forces with Blumhouse following their 2024 merger — meaning this Halloween bet carries the combined weight of the two most commercially successful horror brands of the last decade.
Other Mommy Cast: Who Stars in the Film?
The cast of the Other Mommy Jessica Chastain movie blends an Oscar winner with some of television’s most recognizable faces:
- Jessica Chastain as Ursula and the Other Mommy — the dual lead performance carrying the film.
- Arabella Olivia Clark as Bela, the eight-year-old at the center of the entity’s attention.
- Jay Duplass as Daddo, Bela’s father.
- Dichen Lachman, best known as Ms. Casey on Apple TV+’s Severance.
- Arian Moayed, who played Stewy on HBO’s Succession.
- Karen Allen, the Raiders of the Lost Ark star, in a supporting role.
For Chastain, the dual role is a notable pivot. The Academy Award winner for The Eyes of Tammy Faye is better known for prestige drama, and watching her play both a protective mother and the thing imitating her gives the film a built-in acting showcase that the marketing has leaned into heavily.
Other Mommy Trailer and Release Date
The final trailer for Other Mommy arrived on September 25, roughly two weeks before the film’s theatrical debut. According to Scream Horror Mag, the trailer is “pure nightmare fuel,” and the trade coverage has consistently framed the film as Universal’s headline Halloween-season horror title.
Other Mommy opens exclusively in theaters on October 9, 2026. The date is a classic Blumhouse play — landing the weekend before the mid-October corridor, giving the film a clear runway into Halloween itself. The theatrical-exclusive strategy signals confidence: this is a film the studio wants audiences to experience (and scream through) in a crowded room.
Other Mommy Jessica Chastain Movie Box Office Tracking: A Horror-vs-Drama Oct. 9 Showdown
If early tracking is any indication, Other Mommy won’t just own the Halloween conversation — it could dominate the entire weekend. According to BoxOffice Pro’s long-range forecast (October 2), the film is tracking toward a $15–25 million opening weekend. BoxOfficeTheory, in its October 1 outlook, is even more bullish, projecting as high as $25–35 million, as reported in BoxOffice Pro’s long-range forecast.
Either way, Other Mommy is the clear favorite over its October 9 competition. The weekend’s other major release, Aaron Sorkin’s drama The Social Reckoning, is tracking at just $6–10 million — setting up a genuine horror-versus-drama showdown at the multiplex. For a full breakdown of the other side of that battle, see our coverage of The Social Reckoning and its own October 9 opening.
The matchup is a telling snapshot of the current theatrical market: a Blumhouse horror film anchored by a movie star versus a prestige drama from one of Hollywood’s most decorated screenwriters. The tracking gap suggests exhibitors are betting the same way.
History favors horror in October.
Why Other Mommy Could Be Blumhouse’s Next Big Hit
Several factors are working in the film’s favor. First, the pedigree: a bestselling Malerman novel, a director who already proved he can deliver scares on a tight budget (Host was shot entirely over Zoom during lockdown), and James Wan’s producer imprimatur. Second, the concept is instantly legible — an evil double of your mother is the kind of premise that sells in a 30-second trailer and haunts you long after.
Third, the calendar. October horror releases with recognizable IP or star power routinely overperform, and Chastain gives the film something most Blumhouse titles lack: a genuine movie star at the center of the poster. If the film’s opening lands at the high end of tracking, it would rank among Blumhouse’s strongest recent debuts.
One caveat: horror is the most front-loaded genre in the business, and the two tracking ranges ($15–25M vs. $25–35M) show there’s real uncertainty about the ceiling. The final trailer’s reception and this last week of marketing will decide whether Other Mommy merely wins the weekend or becomes a genuine Halloween-season event.
Other Mommy: FAQ
When does the Other Mommy Jessica Chastain movie come out?
Other Mommy opens exclusively in theaters on October 9, 2026.
What is Other Mommy about?
Eight-year-old Bela forms a chilling bond with an entity inside her home that masquerades as her mother, asking her “Can I go inside your heart?” Jessica Chastain plays both the real mother, Ursula, and the terrifying “Other Mommy.” The film is based on Josh Malerman’s bestselling novel Incidents Around the House.
Who directed Other Mommy?
The film was directed by Rob Savage (Host, The Boogeyman), from a screenplay by Nathan Elston (Succession), and produced by James Wan for Blumhouse and Atomic Monster.
What is Other Mommy’s projected opening weekend?
Tracking ranges from $15–25 million (BoxOffice Pro) to as high as $25–35 million (BoxOfficeTheory), making it the projected winner of the October 9 weekend over Aaron Sorkin’s The Social Reckoning ($6–10 million).
Other Mommy opens in theaters October 9. Check local listings for showtimes.
Leave a Reply
You must be logged in to post a comment.