It's a bird! It's a plane! It's a super hot mess - it's Supergirl! On Thursday, DC dropped the first trailer for their next big screen adventure in Supergirl! House of the Dragon's Milly Alcock stars as Kara Zor-El, the mischievous cousin of Clark Kent/Superman. Related: Zendaya & Robert Pattinson Have Fans Freaking Out After HOT New Movie Poster Release But unlike her super-optimistic family member, she doesn't see "the good in everyone" - she sees the truth.