The 42-year-old actress, who is married to fellow Australian Keith Urban, is often at the centre of Botox rumours due to her youthful appearance.
Kidman, however, says she got out of the wrinkle-smoothing injections because she likes to have control over her facial expressions, the Daily Mail reported.
"No surgery for me; I did try Botox, unfortunately, but I got out of it and now I can finally move my face again."
Kidman credits sticking to a healthy eating plan and rigorous exercise regime for her good looks.
"I am completely natural. I wear sunscreen, I don't smoke and I take care of myself, and I am proud to say that. Anybody can do anything to themselves - I don't judge - but personally I believe in being physically fit. That's how I was raised. I can't go in the sun because I'm fair-skinned. It was a nightmare when I was younger but it has its benefits now."