HBO has added seven cast members to the second season of its four-time Emmy-nominated detective noir series Perry Mason. Katherine Waterston has come aboard as a series regular, joining six new recurring castmembers Hope Davis, Jon Chaffin, Fabrizio Guido, Peter Mendoza, Onohoua Rodriguez and Jee Young Han. In addition, Diarra Kilpatrick who played Clara Drake in Season 1, has been upped to series regular.