Kim Zolciak-Biermann Shocks Fans By Sharing New Photo of 6-Year-Old 'Big Boy' Son Kash

"He is such a BIG BOY he is only 6," Kim Zolciak-Biermann wrote about her son Kash

Kim Zolciak-Biermann‘s son is growing up fast!

On Tuesday, the Don’t Be Tardy star, 40, shared a new photo on Instagram and Twitter of her and husband Kroy Biermann’s 6-year-old Kash sitting in the car.

“My baby @kashbiermann on the way to school this morning! He is such a BIG BOY he is only 6,” Zolciak-Biermann wrote along with a see-no-evil monkey emoji. “He melts me his heart is unreal,” she said, adding the hashtag #HairKing.

In the photo, Kash was placed in a backless booster car seat and dressed in a grey fleece jacket and khaki pants with his hair dapperly styled back.

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Though the former Real Housewives of Atlanta star mentioned her son’s age in the caption, many fans and followers noted Kash’s height and physical development in the comments section.

The mother of six hilariously responded to a fan who left a message about the first grader’s appearance. “Holy hell he looks 25!” the fan wrote with Zolciak-Biermann replying, “Oh your day is coming.”

Another fan commented, “He looks so grown lol,” to which the Bravo star said, “Crazy right!!”

“He does not look 6 , he’s going to be a big boy like his daddy,” wrote one fan.

“Holy cow he does look like he’s 14 or 15 yrs old!” an Instagram user wrote.

Another follower exclaimed, “Lord Kim I was about to say who is this grown man on booster seat. Wow. I think he’s gonna be tall.”

And yet another wrote, “He looks like a 15 year old in a booster! Omg.”

Meanwhile, others criticized Zolciak-Biermann for placing Kash in a booster seat for the car ride. “I’ll keep them in one until they are 18,” she jokingly said, later telling one fan: “See where the seat belt falls… he needs a booster babe.”

Kim Zolciak-Biermann/Instagram

RELATED VIDEO: Kim Zolciak-Biermann Surprises Son Kash With Pit Bull Puppy Four Months After Dog Attack

Zolciak-Biermann often shares updates on her kids — Kash and his siblings Brielle, 21, Ariana, 17, KJ, 6, and twins Kaia and Kane, 5 — all of whom have been heavily featured on their famous mom’s social media.

Most recently, the proud mom raved about Kash’s athleticism when she shared a photo of him from baseball practice. “Another athlete @kashbiermann,” she said on Instagram Dec. 6, referencing Kroy’s former NFL career. “I have big hopes and dreams for my babies but my biggest wish is peace and happiness.”

Earlier this year, Zolciak-Biermann admitted that while she has her hands full at home, she’s still got babies on the brain.

“I went back to work seven days after I had KJ, a couple of weeks after I had Kash, and shortly after I had the twins,” she said while appearing on Steve Harvey‘s talk show. “I didn’t really have a break. So I dream of having a baby, and just six weeks off, and living in that fantasy world.”

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