Married TV stars Carrie Preston and Michael Emerson open up to PEOPLE about Emerson's guest-starring role on 'Elsbeth,' which sees the two going from spouses at home to adversaries on the set of the CBS series.

Michael Emerson, leading lady Carrie Preston's real-life husband and a TV star in his own right, debuts as Milton Crawford in the new episode on December 12. He's not coming on board as a one-off killer like Nathan Lane's character or as another fireman with eyes for Elsbeth,

There’s no love between Carrie Preston and Michael Emerson on Elsbeth. In real life, the couple has been happily married for 26 years. But when they share the screen during this Thursday’s episode of the Good Wife spinoff (airing at 10/9c on CBS),

Elsbeth allowed Carrie Preston and Michael Emerson to play characters that are extremely different from the real-life couple. In Us Weekly‘s exclusive first look at the Thursday, December 12, episode of the hit CBS series,

The writers gave him a great arc, and you’re going to love what he’s done with it, of course!' says Preston of her real-life husband, joining her on her CBS drama.