Brody's wife Leighton Meester has given birth to a baby girl.
The couple, who secretly wed in February 2014, reportedly welcomed their first child together on 4 August but have so far kept their baby out of the public eye.
TMZ reportedly obtained the birth certificate and claim the couple have named their daughter Arlo-Day.
She added: "I like the grown-up stuff. I like having a house. I've got dogs."
McKenzie is best known for playing Ryan Atwood in The O.C and starring in Homeland.
This will be McKenzie's first child, and Baccarin's second. She also has a 23-month-old son Julius with her ex-husband Austin Chick.