The Don't Be Tardy and former The Real Housewives of Atlanta star celebrated her birthday a day early with Brielle, 21.
Zolciak revealed on her Instagram story, as the Bravo website reported, that Brielle had given her a chocolate chip cookie cake with a naughty twist.
It was emblazoned with a pair of white boobs with hot pink nipples rendered in icing, and it read, "Happy 40th Birthday Sugartits."
But don't blame Brielle! Kim explained the joke in her video: "I always call everyone Sugartits."
Zolciak also shared video from her Friday night birthday party on Instagram in which a large number of friends and family members sang her the "happy birthday" song and husband Kroy, 32, and her kids hugged her.
The reality TV wife and mom wore a low-cut tight black dress that flaunted her breasts and high boots to her party.
She wrote as a caption on Saturday, "It's my 40th Birthday ?❤Last night was a dream. I am so grateful, blessed and humbled. There are no words to truly describe how loved I felt and feel. Thank you to everyone that came I truly appreciate you, I love you all from the core of my being. A huge thank you to my INCREDIBLE husband who put his heart and soul into making everything perfect for me I love you @kroybiermann to the moon and back a gazillion trillion times always!"
Brielle loved celebrating her mother's big 4-0 birthday. She showed off her own body by wearing a bikini just before her 21st birthday earlier this year.
When Brielle turned 20 last year, Zolciak shared a shot on Instagram of her daughter thrusting out her breasts.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at email@example.com, or call us at (866) ON-RADAR (667-2327) any time, day or night.