The couple named their new baby girl Brilynn Mari Redmond.
"We are overjoyed with love and beyond blessed welcoming our little miracle. Brilynn shares a birthday with her late grandmother who we honor and miss very much," the new mom said.
"Brilynn has brought so much love and completed our family."
Brandi also shared a photo of the tot on Instagram on Saturday, February 13.
"Valentines came a little early this year💕💞. Welcome our sweetheart, Brilynn Mari Redmond," she gushed as her newborn laid in rose petals shaped like a heart.
"We are so in love," she wrote with another pic of her daughter.
"Gorgeous!!!! So happy for you! Congratulations 💗," one fan gushed.
"Such a little angel ❤️❤️," a second user wrote.
"That hair!!!!!❤️," another noted of the tot’s red locks.
Brilynn joins big sisters Brooklyn 11, and Brinkley, 9, as well as big brother Bruin, 2, and is the couple’s third biological child as they adopted their son in 2018 after suffering a pregnancy loss.
The RHOD star broke the good news in October with a photo of pumpkins displaying her children’s birth years painted on each one... with a fourth pumpkin donning a "2021."
"We decorated pumpkins for our little pumpkin patch this afternoon. God works in mysterious ways and we are so thankful for his grace and glory," Brandi wrote at the time. "You never know what his plan is but we know he’s got us in the palm of his hand."
"We have much to be thankful for this holiday season and want to thank all of you for your prayers, love and out pouring support."
The news of the bun in the oven came shortly after Bryan’s mother, Jill Marie Redmond, lost her life in a car crash. Brinkley was also in the car but survived the accident.
PEOPLE was the first to report on Brandi’s new baby.