Season Regulars 4

1. 

   Michael Sheen

   William Masters

2. 

   Lizzy Caplan

   Virginia Johnson

3. 

   Caitlin FitzGerald

   Libby Masters

4. 

   Annaleigh Ashford

   Betty DiMello

Guest Stars 18

1. 

   Isabelle Fuhrman

   Tessa Johnson

2. 

   Teddy Sears

   Dr. Austin Langham

3. 

   Kevin Christy

   Lester Linden

4. 

   Alex Borstein

   Loretta

5. 

   Joe Tapper

   Keith

6. 

   Bruce Nozick

   Newsweek Journalist

7. 

   Frank Clem

   Zookeeper Steve

8. Leah Verrill

   Female Study Subject in Film

9. 

   Brian Linsley

   Male Study Subject

10. Catie Boles

    Female Study Subject

11. Troy Medley

    Hank the Janitor

12. Christine Robert

    Burlesque Dancer (uncredited)

13. Tracy Rudewicz

    Patient (uncredited)

14. 

    Benjamin Koldyke

    Paul Edley

15. 

    Heléne Yorke

    Jane Martin

16. 

    Josh Charles

    Dan Logan

17. 

    Sarah Silverman

    Helen Schiff

18. 

    Jaeden Martell

    Johnny Masters

Crew 1