Milly Alcock's Supergirl has a brief but hilariously memorable cameo in James Gunn's Superman, establishing her party girl persona along with the basic facts that she's Superman's cousin, and that she's been off-world. And as we see in the movie, the DCU's Kara Zor-El is what James Gunn tells ScreenRant is a "total mess."
"She's a total mess. I mean, I think as we learn, she's had a completely different background from Superman. A much more difficult background," Gunn explains. "He's had this wonderful upbringing by these two parents that loved him and were very healthy. And her background was much different than that."
Alcock will star as Supergirl in the next film in the new DC Universe, in which she'll undergo a transformative adventure based on the comic of the same name. In the comic it's based on, Supergirl: Woman of Tomorrow, Kara Zor-El leads a rebellion on an alien world against tyrannical overlords.
Judging by how she was portrayed in Superman, it seems that she may find herself mostly powerless under a red sun, as well - a fate she often flirts with, according to her cameo.
In comics, Supergirl is from Argo City, a different part of Krypton, and was sent to Earth at the same time as Kal-El. Unlike Kal-El, who was a baby, Kara Zor-El was already a young woman, and was tasked with babysitting her cousin. Unfortunately, her pod went astray, and she didn't make it to Earth till Kal-El had already grown older than her.
Supergirl hits cinemas on June 26, 2026. For more, here are the upcoming DC movies you have to look forward to.
