Masterson, who plays Tara Chambler on the AMC series, took to Instagram late Thursday to share the exciting news. "We did it. @brickstowell," the 27-year-old captioned a photo of her and Stowell locking lips.
On Friday, Stowell shared a photo of their baby's tiny foot up against one of his hands.
Aside from Masterson's baby news, fans of her show were thrilled to learn that The Walking Dead was picked up for a seventh season late last month. The network also renewed the live after-show, Talking Dead, hosted by Chris Hardwick.
As ET previously reported, season six left fans with one big question: Will Glenn (Steve Yeun) still be around for the next season?
SPOILER ALERT! The beloved character was apparently killed off in a recent episode after being pinned underneath Nicholas' lifeless body and (apparently) devoured by a herd of walkers. ETonline's been digging for clues to prove he's still alive. Watch the video below to hear more.