
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."