Jennifer Garner Gives Birth to a Baby Boy!

Us Weekly -- It's a boy for Jennifer Garner and Ben Affleck!

The couple of seven years welcomed their third child, a baby boy, in Santa Monica, Calif., a source tells Us Weekly.

Garner and Affleck's new little one joins older daughters Violet, 6, and Seraphina, 3. Affleck later announced the birth on his Facebook page: "We are happy to announce on February 27, Jennifer gave birth to a healthy baby boy, Samuel Garner Affleck."

PHOTOS: See Jen's cutest mommy moments!

Announcing her pregnancy in August 2011, Garner, 39, managed to stay mum on the gender of her family's third baby, and while she admitted she'd be thrilled to have another girl, she said Affleck was excited either way.

PHOTOS: Jennifer and her girls on the go

"I would have thought [he wanted a boy]. At first ... I really thought so," the actress told Jay Leno in January. "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."

Garner's older daughters had quite a ball acting as a focus group for potential baby names for their brother.

PHOTOS: See how Violet has grown!

The actress joked that she and Affleck entertained their suggestions for baby names -- most of which happen to be Disney-themed. "[They suggested] Donald Duck, Minnie Mouse Affleck," Garner joked. "And then they moved on ... [to] Peter Pan, Captain Hook, Smee."

Keep clicking to see photos of Jennifer Garner throughout her pregnancy ...