Actress joins cast that includes Steve Coogan, Bradley Whitford and Kathryn Hahn
Emmy-winning actor to appear alongside Steve Coogan on the comedy pilot
Actress previously played same role opposite the late Philip Seymour Hoffman
"Philomena" star takes over in network's comedy pilot after Hoffman's February death
TCA 2014: Showtime president David Nevins says casting would need to be "perfectly put together"