The horror phenomenon that redefined indie box office expectations is officially moving to the small screen. A24’s “Backrooms” is scheduled to premiere on HBO Max at 3:01 a.m. ET on Friday, September 25, 2026. For those who prefer a traditional broadcast experience, the film will also make its linear television debut on the HBO channel on Saturday, September 26, at 8 p.m. ET.
The film’s arrival on streaming follows a theatrical run that rewrote the record books for independent cinema. With a global gross surpassing $402.5 million, “Backrooms” has become the highest-grossing film in A24’s history. It comfortably overtook the previous record holder, 2025’s “Marty Supreme,” which earned $192 million, and “Everything Everywhere All At Once.”
From Viral Lore to Box Office Dominance
The transition from internet “creepypasta” to a $400 million blockbuster was led by 20-year-old director Kane Parsons. Originally gaining fame for his viral YouTube series documenting the “liminal space” aesthetic, Parsons has now set a significant industry milestone as the youngest director in history to debut a film at No. 1 at the domestic box office.
The production is also notable for its massive return on investment. Produced on a modest $10 million budget, the film’s $400 million-plus haul makes it one of the most profitable indie releases of the decade. The story expands on the original internet lore, focusing on Clark (Chiwetel Ejiofor), a furniture store owner who discovers a doorway to a sprawling, yellowish liminal space within his own basement showroom.
A Cast of Heavy Hitters
While the film’s roots are in digital culture, its cinematic execution relied on a cast of established dramatic talent. Academy Award nominee Chiwetel Ejiofor leads the film as Clark, navigating the disorienting, endless corridors of the “Backrooms.” He is joined by Renate Reinsve, who portrays Dr. Mary Kline, a character central to the investigation of the anomaly. Mark Duplass also appears in a supporting role.
The film’s success is largely attributed to its ability to translate “liminal space” horror—a genre focused on the unsettling nature of empty, transitional places—into a narrative-driven feature. For viewers who missed the theatrical window, the September 25 streaming launch provides the first opportunity to watch the film as part of a standard subscription.
Following its debut on HBO Max, the film is expected to remain a permanent fixture of the platform’s A24 library, continuing the long-term output deal between the studio and the streaming service.
