The adorable new addition to the family is the first child for Brooke and her husband, Thayer Wiederhorn, and is Richards' first grandchild.
A week before Brooke delivered her baby, she took to Instagram to celebrate her mom's 52nd birthday, where she gushed over how wonderful the reality star is going to be as a grandmother.
"Happy birthday to the most amazing mom in the world! I know you will be an even more amazing grandma!!" Brooke, 30, captioned a sweet mother-daughter snapshot. "I love you!"
Two weeks ago, she bared her belly in this heartwarming black-and-white photo, which she captioned, "Mommy & Daddy Can't Wait To Meet You!"
Back in August, Richards took to Instagram to share a photo of her kissing her daughter's stomach
, and marveled in the caption, "It's amazing how much we love him already."
Congrats to the happy couple and the brand new grandma!