The 59-year-old Australian actress - who shares two daughters, Sunday, 18, and Faith, 15, with ex-husband Keith Urban - explained she doesn't want to prioritise being pals with her kids.
Instead, Kidman, who also shares two adopted children, Bella and Connor, with ex-husband Tom Cruise, would rather her offspring see her as their "rock".
"You're a mother first. You're a mother, but you're also a guide, a mentor, a safe haven, the place you can always come home to," she told the Daily Telegraph.
But ultimately, as I always say to my kids, no, I'm not here to be your best friend, I'm here to actually be the person who is your rock."
Kidman has been doing the rounds promoting her new movie Practical Magic 2, and attended a screening of the film in Sydney on Friday with Faith.
"Sunny is working right now, so she wishes she could have been here, but Faithy got on the plane with me and she's like, 'I'm coming, you're not doing this alone'," she said.
Sunday has been busy forging a modelling career, with Kidman admitting recently it was her own mother who told her to encourage the teenager to follow her catwalk dream.
"As a mother, I'm just, like, 'Okay.' My mother let me do my passion that I wanted when I was 14. Actually, before my mumma passed, she was there and I said, 'Oh, should I let her? She wants to model," she told Entertainment Tonight.
Kidman's mother Janelle replied: "Well, you did it".
"I went, 'okay'. That was sort of my mumma's parting gift to Sunny was [that] she encouraged me to let her be able to follow her bliss and follow her passion and what she wanted. That's exactly what she said, 'You, kind of, have to let her because I let you.'"
Kidman's mother died in September 2025.
Sunday's modelling career is going from strength to strength, and she has already taken on jobs for huge names including Miu Miu, Calvin Klein and Christian Dior.
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