Selma Blair and Jason Bleick welcomed son Arthur Saint Bleick at a private hospital in LA, Blair's rep tells Us Weekly.
Both mother and baby are said to be doing well.
The new-born, who was three weeks overdue weighed in at 7 lbs., 12 oz. It's the first child for Blair and Bleick, who met while collaborating on Bleick's EVER fashion line.
Selma, 39, and Jason announced the pregnancy in January.
"I feel like the luckiest girl in the world," Blair, 39, told Us at her June baby shower, hosted by BFFs Sarah Michelle Gellar, Jaime King, Karen Zambos and Janey Lopaty.
The actress recently teased fans in an interview by refusing to reveal the sex of her child with her fashion designer beau.
"I'm not going to say what it is yet. Hopefully, it's one or the other," she said.
Congratulations to the happy couple!