She's always been a beautiful girl!
"Happy 15th birthday to my little girl! @KaiaGerber you make us so proud every day and we love you so much!" Cindy captioned a darling black-and-white snapshot of herself with her mini-me, a budding model and actress, as a very young girl.
Daddy got in on the social media lovefest too.
"Happy Birthday my sweet angel. You will always be my little girl. Let's dance!" Rande -- a former model and restaurateur who partnered with George Clooney to launch Casamigos Tequila in 2013 -- wrote alongside an old pic of himself dancing with Kaia when she was small.
Three days before her big birthday, Kaia celebrated another milestone when she attended the premiere for her first acting project, the Lifetime TV movie "Sister Cities."
"I'm focusing a lot on modeling right now and it's been pretty busy," Kaia -- who wore a black Zuhair Murad look and strappy Alexa Wagner heels -- told E! News, "but just because this whole experience has been incredible I'm not closing any doors to anything."
As for acting vs. modeling, Kaia admitted that acting was a little outside of her comfort zone at first. "I was more nervous than I usually am, but I think it was just such a warm cast and everyone on set was super nice that they just made it super easy and amazing," she added.
Kaia also told E! that her mom gave her a little bit of advice. "She told me more about being on time, being professional," she said, "but I think it just comes down to your own instincts."
"I've been lucky enough to hang out with them all and see just how nice they are and how unaffected they are," Kaia said. "It's just shown me how you can still have this crazy amount of fame but be nice and not lose that humanity."
Kaia's big brother Presley Gerber, 17 -- who's also launched a modeling career and shared a runway with Gigi's little brother Anwar Hadid in June -- posed alongside his sister at her TV movie premiere.
"So proud of my sis!" he captioned a photo of them in matching zipper-detailed looks on the red carpet.
Rande re-posted the pic, while Cindy shared a snapshot of their entire genetically blessed family at the event together.
"On the red carpet with the family last night -- supporting @KaiaGerber at the premiere of #SisterCities! ❤️," Cindy captioned the photo.
"Sister Cities" debuts on Lifetime on Sept. 17.