Oscar winning musician and Underground executive producer John Legend is taking on an addition role in season 2 of the series. Legend has signed on for a key role in the WGN America drama. The Hollywood Reporter has revealed that Legend will play the role of popular abolitionist and author Frederick Douglass. Douglass was a key figure in the real life efforts of the Underground Railroad. Aisha Hinds (Under the Dome) will also join the cast in a recurring role as Harriet Tubman.