On Supergirl, an executive assistant working at the National City Tribune, Kara Danvers (Melissa Benoist), learns to embrace who she really is — Supergirl — and all the super powers that come with her alter ego. There are only three people who know her true identity — her two co-workers, photographer-turned-art-director James Olsen (Mehcad Brooks) and IT guy Winn (Jeremy Jordan), and her sister Alex. Kara and Alex aren’t blood sisters — Alex’s family adopted Kara — but they share their secrets with each other as blood sisters do. Plus, it helps that Alex works for the Department of Extra-Normal Operations, a big supporter of Supergirl.
Alex Danvers is portrayed by Chyler Leigh. She’s best known for her roles as Dr. Lexie Grey on Grey’s Anatomy and Private Practice, as Detective Caitlyn Sullivan on Taxi Brooklyn, Claire Wyatt on The Practice, June Tuesdays on That ‘80s Show, and Frankie on 7th Heaven. Supergirl airs Mondays at 8:30pm on CBS, right after The Big Bang Theory.