If 2022 was the year Milly Alcock became a household name as the silver-haired Rhaenyra Targaryen, 2025 was the year she proved she didn’t need a dragon to command the screen. In Netflix’s biting dark comedy “Sirens,” Alcock sheds the medieval regality of Westeros for the sharp-tongued, silk-clad world of the ultra-wealthy. Playing a young woman caught in the intoxicating web of a socialite’s cult-of-personality, Alcock delivers a performance that is as vulnerable as it is volatile. As we look ahead to her debut as the DC Universe’s Supergirl in 2026, it’s clear that Alcock is no longer just a rising star—she is the blueprint for the next generation of Hollywood icons.
The Simone Transformation: Trading Scales for Silk
In “Sirens,” which premiered on Netflix in May 2025, Milly Alcock plays Simone DeWitt, a young woman who has traded her middle-class roots in Buffalo for the high-stakes, “Lilly Pulitzer” lifestyle of a personal assistant. Working for the enigmatic and philanthropic socialite Michaela Kell (played by Julianne Moore), Simone becomes deeply entrenched in a world of excessive luxury that her older sister, Devon (Meghann Fahy), finds increasingly disturbing.
Alcock’s portrayal of Simone is a masterclass in psychological nuance. She captures the frantic energy of someone “climbing the social ladder” while battling secret panic attacks and an obsessive need for approval from her employer. The dynamic between Alcock and Moore is the series’ beating heart, a “toxic sisterhood” that explores the seductive and destructive nature of extreme privilege and power.
A Sisterly Intervention: The DeWitt Dynamic
The narrative engine of the five-episode miniseries is the friction between Simone and her sister Devon. When Devon arrives at the Kells’ lavish estate for a surprise visit, she discovers a version of Simone she doesn’t recognize—one who has been “brainwashed” by the Kells’ cult-like lifestyle. The chemistry between Alcock and Meghann Fahy provides the show’s most grounded moments, offering a sharp contrast to the absurd wealth surrounding them.
Critics have praised Alcock for her ability to hold her own against veterans like Moore and Kevin Bacon. Her Simone is not a passive victim; she is a formidable participant in the psychological games played at the estate. This role successfully bridged the gap between Alcock’s fantasy roots and the contemporary “rich-people-behaving-badly” genre that has dominated the mid-2020s.
From Sydney to the West End: The Artist’s Journey
Milly Alcock’s path to “Sirens” was paved with bold professional risks. In 2018, she famously dropped out of high school in Sydney during her final year to join the cast of the Australian drama Upright. That gamble paid off, leading to her breakout in House of the Dragon and eventually a prestigious stint on the London stage. In 2024, Alcock received critical acclaim for her portrayal of Abigail Williams in The Crucible at the National Theatre.
This theatrical training is evident in her performance in “Sirens.” She brings a physical intensity to Simone that feels lived-in and raw. Whether she is dodging her sister’s questions or engaging in a flirtatious affair with a business tycoon (played by Glenn Howerton), Alcock moves through the frame with the confidence of an actor who has spent years honing her craft on both the stage and the screen.
The Supergirl Shift: A New Era of DC
While “Sirens” dominated the conversation in 2025, the industry is already bracing for Alcock’s next giant leap. Having made a brief, scene-stealing cameo in James Gunn’s Superman (2025), Alcock is set to lead her own solo film, “Supergirl: Woman of Tomorrow,” scheduled for release on June 25, 2026. Her interpretation of Kara Zor-El—described by Gunn as a “drunken party girl” with a dark, cosmic edge—is a radical departure from previous versions of the character.
Directed by Craig Gillespie, the 2026 film is expected to be a “space adventure” that explores Supergirl’s trauma and resilience. Alcock’s casting was reportedly a “no-brainer” for Gunn after seeing her in House of the Dragon. Her ability to project both “humanity and vulnerability” while handling large-scale action sequences has made her the perfect choice to anchor the new DC Universe’s first major female-led film of the “Gods and Monsters” chapter.
Fashion’s New Muse: The Alcock Aesthetic
Beyond her acting, Alcock has become a fixture in the 2026 fashion world. Her style is a blend of “edgy indie” and “high-fashion refinement,” often seen sitting front row at Louis Vuitton and Fendi shows. For the “Sirens” press tour, she leaned into the “sheer and sculptural” trends of the season, further distancing herself from the period costumes that first made her famous.
She represents a new breed of celebrity—one who is academically minded (she is an avid photographer) but stays grounded in her Sydney roots. Whether she is milling around Manhattan’s East Village or walking the red carpet in Cannes, Alcock carries herself with a “cool-girl” nonchalance that has endeared her to Gen Z and Millennials alike. She isn’t just playing a socialite in “Sirens”; she is becoming a genuine cultural icon.
The Legacy of a Multi-Hyphenate
As we look toward the 2026 summer blockbuster season, Milly Alcock stands at the pinnacle of her career. From the dragons of Westeros to the social battlegrounds of “Sirens,” and finally to the stars of the DCU, she has proven herself to be one of the most versatile actors of her generation. Her performance as Simone DeWitt remains a highlight of 2025, a dark, comedic turn that reminded audiences of her range and magnetic screen presence.
The story of Milly Alcock is one of constant evolution. She is an actor who refuses to be pigeonholed, consistently choosing roles that challenge expectations. Whether she is flying through the cosmos or navigating the complex politics of a beach estate, Alcock remains “the one to watch.” In the world of 2026, she isn’t just a siren—she is the storm.
