Michael Sheen and Lizzy Caplan have landed the lead roles in Showtime's titillatingly titled drama pilot "Masters of Sex."
 
Showtime announced on Thursday (February 2) that Sheen will play William Masters and Caplan will be Viginia Johnson in "Masters of Sex," which focuses on the "human sexuality pioneers."
 
Masters and Johnson began their research at Washington University in 1957, culminating in the publication of the seminal -- pun horribly intended -- texts "Human Sexual Response" and "Human Sexual Inadequacy," published in 1966 and 1970. The Showtime series is an adaptation of Thomas Maier's "Masters of Sex: The Life and Times of William Masters and Virginia Johnson, The Couple Who Taught America How To Love."
 
"Masters of Sex" will begin production in New York in March with John Madden ("Shakespeare in Love," not the football guy) directing and Michelle Ashford, Judith Verno, and Sarah Timberman and Carl Beverly executive producing.
 
Sheen is stepping in for Paul Bettany, who was originally cast in the pilot. We'd like to say that he's best known for films like "The Damned United," "Frost/Nixon" and his Tony Blair trilogy, but realistically popular audiences know him from the "Twilight" and "Underworld" films, not that there's anything wrong with that.
 
Caplan's TV credits include a current arc on "New Girl" as well as regular roles on "Party Down," "The Class" and "Related." She was recently up at Park City for the Sundance premieres of the features "Bachelorette" and "Save the Date."