NEW YORK -- Michael Emerson has played a serial killer, a mysterious, villainous Island leader and currently stars as a billionaire computer genius on "Person of Interest." But he says playing the romantic interest for his real life wife has been his most unsettling role.

Emerson plays the off-beat Harold Finch in "Person of Interest," which airs Thursdays at 10 p.m. His wife Carrie Preston has a recurring role as Finch's former fiance, who believes he is dead.

The couple has acted together in a few independent films and Preston even played Emerson's mother in an episode of ABC's "Lost," but this was their first romantic pairing. This season even showed the characters' first kiss.

Emerson said having his wife play his love interest can be tricky: "It's a little hard to turn off her wife-ness to me to make her just this other character."

Preston, who also appears in "True Blood" and "The Good Wife," also found working with him a little strange but that nothing was more bizarre for them than watching the kiss on TV.

"We both sat and watched it together at home on the sofa and we got all kind of giggly and shy about it," he said. "It's like, ‘Oh God, there we are. We're kissing.' "