The actress gave birth to a baby boy on Monday at a clinic in Santa Monica, Los Angeles.
“We are happy to announce that on February 27, Jennifer gave birth to a healthy baby boy, Samuel Garner Affleck,” Affleck posted on his official Facebook page this morning.
The baby boy joins the couple’s daughters Violet, 6, and Seraphina, 3.
The pair announced they were expecting their third child in August 2011 and decided to stay mum on the baby’s gender.
But while Jennifer admitted that having a girl would be a great idea, she said her hubby was excited either way.
“I would have thought [he wanted a boy]. At first…I really thought so,” she told Jay Leno last month. “And then [Ben] kind of said, ‘Well, we have girls. We know how to do girls. My girls love me. I’m the big guy in the house.’ So, now I’m not sure.”
Earlier this month, the Alias star revealed that she and Ben let their two daughters pick a name for their younger sibling.
“Our girls are working on names. At first they were definitely Disney. It was like, Donald Duck, Minnie Mouse Affleck. And then they’ve moved on. Then it was Peter Pan, Captain Hook, Smee,” she told E! Online.
“They’re coming up with lists and coming in and saying, ‘Let’s have a baby-naming contest! Let’s have a baby-naming poll!’ They ask everyone, because they just want to know. But we’re not telling.”
Garner and Affleck, both 39, married in June 2005 at a private ceremony in Turks and Caicos, in the Caribbean.