Who Is Milly Alcock? 6 Things to Know About the 'Supergirl' Star

Milly Alcock has officially donned Supergirl's cape and taken flight in the DC Universe.

Supergirl, which premiered on June 26, stars Alcock as Kryptonian Kara Zor-El. The DC film also features Jason Momoa as Lobo and David Corenswet as Kal-El, also known as Clark Kent and Superman.

Following the movie's theatrical release, here's everything to know about the new Supergirl.

Alcock was born in Sydney, Australia, on April 11, 2000, and was raised by a single mother who worked as a nanny, per Vanity Fair.

"She was a single mum and raised the three of us," she told Vogue Australia. "My two younger brothers don't work in the arts, so there is that sense of otherness in the work, but in terms of who I am and the way they treat me, I'm still Milly. We're all very close in age; they're also growing and changing as am I, and my mother is dealing with having an empty nest, but she has a wonderful partner now. I guess we're all in this growing-pains period together."

She moved to London during the COVID-19 pandemic to further pursue her acting career.

In an interview with Variety, Alcock revealed she "never lived out of home before" and "had not really traveled." She then found living alone in London "very exciting" but also "very daunting."

She explained, "Didn't know how to use the washing machine. I was learning how to look after myself properly: How do I function as a human? I was very independent, but that's a whole other journey of having to live alone and not know anyone in a new city, and have this big pressure in how you deal with that stress."

Alcock attended Newtown High School of the Performing Arts, which she credits with laying the groundwork for her acting career.

"It was drama school, so it was like 'walk around like you're in mud'. Ultimately, the point of those silly activities is to let go of ego, to let go of perception," she said, adding, "Acting is so embarrassing and [is] incredibly liberating."

At the time, she balanced commercial work and auditions with jobs at cafés and restaurants.

She launched her acting career after joining the cast of the Australian sitcom Upright, an opportunity that prompted her to leave school and pursue acting.

"My mother instilled this blind confidence within me: 'If those idiots can do it, why can't you?' Her words, not mine,” she told Vanity Fair. "It just lit a fire under my a--."

Alcock shared in a separate interview with Vogue Australia that she knew the opportunity "would be so much more of a valuable experience than getting [her] piece of paper."

"I never doubted it for a second," she admitted. "I was almost too impulsive. I was like: 'No, this is what I've been working towards and I've been given this amazing opportunity with this amazing cast, with this beautiful script.' I couldn't say no and I couldn't let the fear and anxiety of not finishing school haunt me, because that would have defeated the whole purpose of leaving."

While starring in Upright, Alcock was still living in the attic in her family home because they "didn't have enough rooms."

"It was so hot in there," she said.

Although she was already acting, she continued washing dishes at a popular Sydney restaurant.

She shared with Variety in May, "I was a stick of a thing. I was washing these dishes so proudly and so terribly, and it was an open kitchen so everyone could see me."

Alcock has starred in several TV shows so far, including The Gloaming and Reckoning.

She scored her breakout role as the young Rhaenyra Targaryen in House of the Dragon, a prequel to Game of Thrones.

"I couldn't book a role in an independent film until I had done a franchise," she told Variety. "I didn't really work a year after House of the Dragon. I did one play that year."

After completing her work on House of the Dragon, she went back to Australia to film Upright Season 2.

Alcock is in a relationship with London-based chef Joseph "Jo" Powell.

The couple went public with their relationship in a June 2025 Instagram post, which featured Powell wearing an "I Love My Girlfriend" shirt. She lives with Powell and their Persian cat, Guinness, in London.

Alcock first joined the DCU in the James Gunn-directed 2025 film Superman, paving the way for her to reprise the role in Supergirl and in the upcoming Superman: Man of Tomorrow.

"I'm going to burst into tears," she said before the 2026 DCU film was released. "I am so excited for all the young women who are going to see this — that's really going to get me."

Reflecting on landing her first major leading role, she told Vogue Australia, "It comes with its own expectation, but the opportunity it's given me is to learn and expand who I am personally and professionally."