Laura Benanti, Dylan Baker

Laura Benanti has just landed a plum role on The Good Wife, but she may not be sticking around long.

The Tony-winning actress has been cast as the new fiancée of wife killer, and frequent Lockhart / Gardner client, Colin Sweeney (Dylan Baker), TVGuide.com has learned.

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Sweeney will return when Alicia (Julianna Margulies) tries to represent him on a civil case. "They both get into a little legal trouble that Alicia is witness to," executive producer Robert King tells TVGuide.com of the new couple. "[Alicia] has to play the part of a witness in a case."

Little is known about Benanti's character, but executive producer Michelle King says she's "beautifully suited for Colin Sweeney." Uh, does that mean she has a dead spouse buried somewhere too? 

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Known for her roles on Law & Order: SVU, Royal Pains and Go On, Benanti most recently wowed critics and viewers with her performance of Elsa on The Sound of Music Live! Baker, who has earned two Emmy nominations for his performance as Sweeney, most recently guest-starred on Chicago Fire.

The Good Wife airs Sundays at 9/8c on CBS. Benanti's episode, directed by star Josh Charles, is slated to air later this season in either late April or early May.

(Full disclosure: TVGuide.com is owned by CBS.)