It's a boy for Jennifer Garner, Ben Affleck

Jennifer Garner and Ben Affleck have welcomed their third child -- a son -- in Santa Monica, Calif., People magazine reports.

The new addition joins big sisters Seraphina, 3, and Violet, 6.

The couple announced the pregnancy in August, and managed to keep the baby's gender a secret. During a visit with Ellen DeGeneres, Garner said "it would be so weird to have a boy," but that the experience would be "cool and different."

Affleck, in turn, said in 2010 that the three-against-one female-to-male ratio in his house leaves him significantly outnumbered.