Milly Alcock might be suiting up as the next Supergirl in the new DCU movie next year, but her next post-cape project is sounding more like Saw than Smallville. The House of the Dragon breakout and Supergirl lead is set to star in a psychological survival thriller. If that wasn’t already enough to get die-hard fans of new horror movies excited, Alcock will be starring alongside horror genre royalty, Toni Collette, in what’s truly a wild-sounding film.
The Reckoning alum will co-star with Collette in Hot Mother, the debut feature from Australian writer-director Lucy Knox, per Deadline. The plot is simple and suffocating: a mother and daughter check into a remote wellness retreat for some quality time… only to end up trapped inside a sauna with no way out and no one to hear them scream. What follows is a tense, physically brutal fight for survival that leans heavily into both psychological horror and raw endurance. Needless to say, a DC hero would be invaluable in this tale.
The project marks a major return to genre for Collette, who practically has “trauma horror icon” on her resume thanks to Hereditary, The Sixth Sense, Velvet Buzzsaw, and, more recently, the thriller series Wayward, available with a Netflix subscription. Alcock, meanwhile, has been steadily expanding her post-HOTD resume with recent roles in Netflix’s Sirens and her high-profile upcoming DCU Chapter 1 project, set to hit theaters on June 26, 2026.
Hot Mother is being produced by Carver Films (Relic, Run Rabbit Run) and Rapt Films’ Oscar-winner Alex Coco, who recently produced Sean Baker’s Anora. The film will shoot in Australia and is backed by Screen Australia, Screen NSW, and VicScreen, with Maslow Entertainment handling local distribution. Bankside Films is overseeing global sales and co-repping North America with CAA Media Finance, and they seem just as smitten with the film’s twisted premise as the cast.
“We were sold on Hot Mother from the title alone,” Bankside’s Stephen Kelliher told Deadline, adding that the mother-daughter core will help elevate the film from just another survival flick into something with real emotional weight. Producer Anna McLeish echoed that, saying Knox is “beyond ready to bring Hot Mother to life,” while Coco called her a “filmmaker’s filmmaker” poised to leave a global mark.
The original Hot Mother short film premiered at the Berlin International Film Festival in 2020, where Knox turned a sauna into a pressure cooker of character, tension and sweat-soaked dread. So, while the premise might sound minimal, the emotional stakes are shaping up to be huge, and with actors like Collette and Alcock at the center of it, it’s bound to burn in all the right ways.
No official release date has been announced, but Hot Mother is reportedly being lined up for 2026 movie schedule debut, giving Alcock just enough time to trade her red cape for a towel and a bottle of water. In the meantime, you can catch her in Sirens or revisit her breakout role as young Princess Rhaenyra in House of the Dragon Season 1, streaming now with an HBO Max subscription.