Actress Nicole Kidman is afraid that her children will grow too fast and has already imposed a ban on getting tattoos.

The Oscar winning actress sees her 15- and 12-year-old kids already displaying streaks of rebellion, reports imdb.com.

She said: "Bella had a phase of blue hair - luckily that only lasted for a little while. But we recently had a discussion at home about tattoos and I had to lay down some ground rules.

"My husband (Keith Urban) has tattoos, so obviously I don't mind them on principle. But I do think you have to be a certain age before you can choose to do something as permanent as that, and I don't think that age is 14 or 15. Call me old-fashioned, if you will."