TMZ found the "proof" Thursday, nestled in some court documents that relate to Baccarin's ongoing divorce from director Austin Chick.
Baccarin, 36, and Chick, 44, married in 2011 and have a one-year-old son together. Austin filed for divorce from Morena this past July, citing the typical Hollywood reason - "irreconcilable differences."
According to that paperwork, the Homeland actress has asked a judge for full physical custody of her baby on the grounds that, due to her pregnancy, she won't be able to travel between New York and Los Angeles in the coming months.
She lives in NYC - where Gotham is filmed - and Austin lives in Southern California.
Fun fact: Baccarin plays a love interest to McKenzie's Jim Gordon on the Batman-inspired drama. The characters first hooked up in the second half of the first season, much to the dismay of the rogue police officer's psychotic fiancé Barbara Kean. The prequel series returned for its second season this past Monday and airs on Fox.
It's being reported that Baccarin is in her first trimester and simply being proactive before she is too pregnant to fly back and forth.
And while it was worth noting Austin could've been the father based on the timing, Us Weekly confirmed with both Morena and Ben's reps that The O.C. star is, in fact, the baby daddy.
No word from either actor on the exciting news, not even to confirme their relationship, but it's going to have to come quick if they intend to keep walking red carpets together through the rest of awards season.