The 41-year-old reality star and mother of six opened up to ET's Brice Sander at BravoCon in New York City on Friday, where she talked about her second child's recent transformation. Ariana rocked Kim's old Playboy bunny costume for Halloween, prompting lots of social media reactions from followers and trolls alike.
"Well, she's 18 now, so it was like, 'Do it!'" Kim told ET. "I think she's been dying to be 18 so that she could do something like that or do her lips or do whatever – she's been dying to be 18."
Kim thinks some fans struggle with Ariana looking more grown-up because they've watched her from a very early age.
"She's been on camera since she was four years old," Kim noted. "She was four on Real Housewives of Atlanta... and she had a Halloween party and she was like, 'Mom, I need one of your costumes, like, what am I going to do?' And I was like, 'I don't know. What do you want? I don't really dress up, sweetie. All I have is that Playboy costume,' and she's like, 'I'll try it,' and it worked. And so it wasn't like she had planned for it, but it worked out and she looked great in it."
Kim also shared that her daughter is interested in getting lip fillers just like her and her eldest daughter, Brielle.
"She's blessed in that arena, but, you know, after watching Brielle and I, she's probably a little bit more motivated," Kim admitted. "But I'm like, 'You're 18.' Until you're 18 you can't do anything and that's kind of been the rule in my house, so she turned 18 a month ago, so we're doing OK."
In addition to Ariana's interest in looking like her famous mom, Kim's youngest daughter, Kaia, 5, is obsessed with her parents' wedding video.
"Kaia watches our wedding at least twice a week, so we actually see it as well," she said of her 2011 nuptials with husband Kroy Biermann. "She loves to watch the wedding. But we try to watch it every year on our anniversary just to kind of remind us where we came from and how much we've grown. Thankfully, I'm very much in love with him, so I don't need a reminder of how much I loved him then because I actually love him more today."
Of her husband, she addded, "I just think Kroy was literally made for me. You know, we just connect -- emotionally, sexually, just the whole nine yards. It just kind of works and he's great and he gets me and he lets me be me, and I think that's a big thing."