Supergirl: DC’s James Gunn Confirms Milly Alcock’s Casting

James Gunn and Peter Safran’s DC Universe is beginning to take shape — and it looks like it has officially cast its latest heroine. On Monday, shortly after news outlets began to report that Milly Alcock has been cast as Kara Zor-El / Supergirl in the DC Universe, Gunn took to his Instagram to confirm the news. Alcock, who is best known for her work on HBO’s House of the Dragon, is rumored to first appear in Superman: Legacy, which is written and directed by Gunn and expected to begin production later this spring. She will then star in  her own cosmic adventure film Supergirl: Woman of Tomorrow, which is one of the first five feature films announced for Gunn and Safran’s DCU. Woman of Tomorrow will be based on Tom King and Bilquis Evely’s recent twelve-issue comic miniseries of the same name.

“This is accurate. Milly is a fantastically talented young actor,” Gunn’s post reads.

Who Is DC’s Supergirl?

Created by Otto Binder and Al Plastino in 1959’s Action Comics #252, Kara Zor-El is the cousin of Clark Kent / Superman, who is also sent to Earth from their dying home planet, Krypton. Shortly after her debut, Supergirl appeared in a backup strip in Action Comics, and became a public-facing superhero beginning in 1962. She made an array of comic appearances — including a 23-issue solo series — leading up to 1985’s Crisis on Infinite Earths crossover, in which she was killed off in an effort to streamline continuity. The mantle of Supergirl was held by multiple women in the years to follow, including Linda Danvers, Cir-El, and eventually Kara herself when she was brought back to life in 2004. 

Supergirl has been portrayed onscreen a number of times over the years, across film, television, and animated projects. In live-action, she has been played by Helen Slater in the 1984 film Supergirl, Laura Vandervoort in later seasons of Smallville, Melissa Benoist on the Arrowverse’s Supergirl television series, and Sasha Calle in last year’s The Flash movie.

What Is Superman: Legacy About?

Per DC Studios, Superman: Legacy tells the story of Superman’s journey to reconcile his Kryptonian heritage with his human upbringing as Clark Kent of Smallville, Kansas. He is the embodiment of truth, justice and a better tomorrow, guided by human kindness in a world that sees kindness as old-fashioned.

Superman: Legacy will also star David Corenswet as Clark Kent / Superman, Rachel Brosnahan as Lois Lane, Skyler Gisondo as Jimmy Olsen, Nicholas Hoult as Lex Luthor, Sara Sampaio as Eve Teschmacher, María Gabriela de Faría as Angela Spica / The Engineer, Isabela Merced as Kendra Saunders / Hawkgirl, Nathan Fillion as Guy Gardner, Edi Gathegi as Michael Holt / Mr. Terrific, and Anthony Carrigan as Rex Mason / Metamorpho.

Are you excited for Superman: Legacy? What do you think of Milly Alcock’s Supergirl casting? Share your thoughts with us in the comments below!

Superman: Legacy will be released exclusively in theaters on July 11, 2025.