What role made Milly Alcock famous before she was cast as Supergirl?

Milly Alcock became widely recognized and celebrated for her role as the young Princess Rhaenyra Targaryen in the HBO fantasy series House of the Dragon, which premiered in 2022. The show serves as a prequel to Game of Thrones, set roughly 200 years before the events of that series, and focuses on the Targaryen civil war known as the Dance of the Dragons. Alcock portrayed Rhaenyra during the earlier portion of the story, depicting the character as a teenager and young woman navigating the treacherous politics of the Iron Throne while asserting her claim as her father King Viserys's chosen heir. Her performance in House of the Dragon was met with widespread critical acclaim. Alcock brought considerable depth and complexity to Rhaenyra, portraying her as fiercely independent, politically astute, and emotionally layered. The character faces enormous pressure as a woman trying to secure a succession that many in the patriarchal society of Westeros refuse to accept, and Alcock conveyed that tension with remarkable skill for someone who was still a relatively emerging talent at the time. Critics frequently singled her out as one of the standout elements of the show's first season, and she quickly became a fan favorite. Before House of the Dragon, Alcock had worked in Australian television, appearing in shows like Upright and Rogue, but she was largely unknown to international audiences. Her casting as young Rhaenyra represented a significant leap onto the global stage, and she made the most of the opportunity. Emma D'Arcy took over the role of Rhaenyra as an adult in the later episodes of the first season and into the second season, but Alcock's portrayal left such a strong impression that she remained a prominent topic of conversation even after her character aged out of her portion of the story. The success of House of the Dragon and the attention Alcock received for her work in it directly led to her being cast as Kara Zor-El, also known as Supergirl, in the DC Universe film Superman, directed by James Gunn and released in 2025. Gunn has spoken about how her talent and screen presence made her the right choice for the role, which is set to be a significant part of the new DC Universe he is building. The casting was announced to considerable excitement, with many fans expressing enthusiasm about seeing the actress take on such an iconic superhero role following her breakout work in the Targaryen saga. Alcock's trajectory from Australian television to one of the biggest fantasy series in the world and then to a major superhero franchise represents one of the more remarkable rises in recent Hollywood history. Her work as young Rhaenyra demonstrated a range and charisma that clearly caught the attention of major filmmakers and studios, and her casting as Supergirl suggests that her profile will only continue to grow in the coming years.