The Gotham stars welcomed their first child on March 2.
And the little one's got an adorable vintage baby name: Frances Laiz Setta Schenkkan.
"Morena and Ben are so happy to welcome baby girl Frances Laiz Setta Schenkkan on March 2," reps Jennifer Allen and Rhett Usry confirm to USA TODAY. "All are happy and healthy and appreciate the well-wishes."
Both Barccarin, 36, and McKenzie, 37, star on Fox's Batman prequel Gotham - in which they play characters who are also expecting a baby.
Baccarin told People the Gotham plotline dovetailing with the couple's real-life was "a total coincidence. They were already planning on doing that with (our) characters when I got pregnant. When I told them they were like, 'Okay, great!' and I was like, 'What?' It worked out perfectly."
This is McKenzie's first child. Baccarin has a 2-year-old son, Julian, with her estranged husband, Austin Chick.
Baccarin recently championed through the Deadpool press tour in February, calling herself "a million months" pregnant while visiting Access Hollywood. "No sudden moves, anybody," she joked.
The R-rated superhero film, led by Ryan Reynolds, soared to the top of the box office, having pulled in $315 million to date.
Congratulations to the happy couple!