Supergirl is one of the biggest female roles in TV at the moment, and you'd imagine it was a highly sought after. The opportunities for women to be the lead in a comic book series aren't all that frequent (more's the pity, based on Supergirl and just how awesome Jessica Jones looks), so it highlights just how perfect a fit Benoist is that she was the one to get the gig. Even more impressive, or perhaps just evidence of how Greg Berlanti's casting process works, is that she was the first person to audition for the role. It took a further ten auditions, three screentests, and a number of months, but finally the part was hers. Clearly the trick to getting the lead part on a Greg Berlanti DC show is to be first. Grant Gustin was the first actor to audition for the role of Barry Allen/The Flash, while Stephen Amell was first for Oliver Queen/The Arrow. Not that there can be any complaints about the choices, of course.