Look, up in the sky: it's a bird, it's a plane! It's...Supergirl! This fall, Supergirl will be joining the lineup of burgeoning superheroes and villains in . Supergirl is the latest DC Comics character to join the series that has previously welcomed Martian Manhunter, The Green Arrow, The Flash, Aquaman, Cyborg and Brainiac. Casting for the Supergirl role is currently underway. airs on Thursdays at 8:00-9:00 p.m. ET on The CW.