The "True Blood" star will play the role of Theo Galavan, the brother to Tabitha Galavan aka DC Comics infamous villain Tigress, reported Aceshowbiz.
Theo is a charming billionaire who pretends to be a hero while, fueled by old vendetta, planning to cause havoc in the Gotham City with his sister.
Their plan is expected to lead to the destruction of some old villains and the creation of new ones.
Benjamin McKenzie is set to return as Detective James Gordon, Nicholas D'Agosto will reprise his role as Harvey Dent, and Morena Baccarin is back as Dr Leslie Thompkins after recurring in the first season. The actress who will play Tabitha hasn't been announced.