The Real Housewives of Atlanta star welcomed a son, Kroy Jagger Biermann, the reality star announced via Twitter Tuesday night.
"[Kroy Biermann] and I are happy to announce the birth of our son today," she wrote. "Kroy Jagger Biermann is healthy & beautiful We are so in love!"
This is the first child for Zolciak, 32, and her Atlanta Falcons boyfriend Kroy Biermann, 25. Zolciak also has two daughters, Brielle, 14, and Ariana, 9, from a previous relationship.
Biermann also Tweeted the happy news, writing, "Thank you everyone for all of your well wishes!! KJ is doing so well along with momma ... Thank you God!!!"
Once she made it into her second trimester, the reality star told PEOPLE she felt "awesome" and emphasized how excited her daughters were to have Kroy in their life – and a new baby on the way.
"He's really fantastic with my girls," Zolciak said of her boyfriend. "I couldn't have asked for a better partner ever."
Zolciak also said she got support from her Atlanta costars Kandi Burruss and Sheree Whitfield. "[Sheree will] send me text messages [like], 'I hope you're not overdoing it,'" Zolciak said, "and 'Do you need anything?' "