Fresh off the news that his former "The O.C." costar Gotham" costar Morena Baccarin.



News broke on Thursday that the pair -- who have been dating in real life while their onscreen alter egos, Detective Jim Gordon and Dr. Leslie Thompkins, are also dating and living together on the hit Fox show -- will become parents. This will be the first child for McKenzie; Baccarin has a 23-month-old son, Julius, with her estranged husband Austin Chick, who filed for divorce from the actress earlier this summer.



The pair first stepped out publicly together last weekend, where they attended the Fox Emmys party on Sunday night as a couple. Reps for both Baccarin and McKenzie later confirmed the baby news to People and Us Weekly.



" and Ben are very happy about this news," a source told People. "Everyone is very excited."



Congrats to the parents-to-be!







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