Tate Donovan Tate Donovan

Tate Donovan is climbing into bed with Masters of Sex, so to speak.

The actor will guest-star in two episodes of Showtime's sexy period drama, in which he'll play opposite Allison Janney in her Emmy-winning role.

Josh Charles is returning to TV on Masters of Sex

Donovan will play Graham, a scientist whose relationship with Margaret Scully (Janney) brings them to Masters and Johnson's clinic. Relationship? Perhaps Margaret has finally found someone else to give her joy in the bedroom. Donovan joins The Good Wife's Josh Charles and Maggie Grace, who have also signed on for the series' third season.

When Masters of Sex returns, it will pick up in 1966, when Masters (Michael Sheen) and Johnson (Lizzy Caplan) are dealing with the national spotlight as their sex study is finally unveiled.

Masters of Sex premieres July 12 at 10/9c on Showtime.

(Full disclosure: TVGuide.com is owned by CBS, one of Showtime's parent companies.)

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