CBS and DC Entertainment have announced that actress Chyler Leigh (Grey's Anatomy) and David Harewood (Homeland) have joined the cast of 'Supergirl.'  Leigh will play Kara's foster-sister Alexandra "Alex" Danvers. Fascinated by Kara’s powers from a young age, Alex developed a lifelong obsession with science, which inspired her to become a doctor. Harwood will play supervillain Hank Henshaw, a onetime … Continue reading Chyler Leigh & David Harewood Join ‘Supergirl’ Cast