Zolciak-Biermann posted the photo of herself with daughter Brielle, 22, showing off a much darker look:
"I had dark hair almost black until I was about 15, that’s when I started coloring it!" the 40-year-old star of "Don't Be Tardy" revealed in the caption. "My mom is a hairdresser so I was always playing around with color. I went blonder and blonder and have never looked back! I don't miss the dark hair although I would take it over all my gray now any day."
It's a wig, of course; Zolciak-Biermann says she'd never go back to full-time brunette. But now that she's basically "100 percent gray," as she told TODAY Style, she's having to dye her hair frequently and alternate with wigs.
"My own hair is pretty dark right now, but not that dark," she said. "I'd be depressed if I were to go fully dark."
The wig turned out to be a happy accident: She had ordered the wrong one and, when it arrived, she wasn't sure if the reddish undertone was right for her. But after putting it on (including wearing it as part of a Halloween costume), she got so many compliments and decided to keep it.
Wigs are essential to her overall look, she explained. "I sit in a makeup chair for an hour, hour and a half every day," she said. "Then I'd have to spend another hour if I didn't use a wig, and I can't do that again. All in all, I feel very sexy with the wig on. It's definitely a change."
In case you couldn't tell, Zolciak-Biermann loves wigs — she's talked about trying to start her own affordable wig company. Right now she's gearing up to sell some of the 150-plus styles she's collected over the years, with proceeds going to charity.
And, yes, the wigs have their own closet.
"I just built a whole space for them," she said. "We're washing and styling them for sale, so probably by early May we'll be selling them."
In the end, whether wigging out or getting dyed, Zolciak-Biermann says never letting all of that gray take over.
"Not happening," she said. "I've looked at people who do that and they're striking, but I can't imagine doing that!"