Nicole Richie believes the best thing about being a mother is she gets to live her ''childhood all over again.''

The 33-year-old fashion designer has daughter Harlow, seven, and son Sparrow, five, with her husband Joel Madden and has admitted she enjoys being a mum because she gets to do all the things she used to do as a youngster but through her kids.

Speaking to news.com.au, she said: ''I get to live my childhood all over again. My daughter is seven, so we're starting to watch all the fun movies together, like 'The Sound of Music'.

''You know, I've been wanting to re-watch those movies, but I've been too embarrassed to watch them by myself.''

The brunette beauty - who went to rehab, dabbled with drugs and alcohol, got arrested and was regularly seen stumbling out of nightclubs in her teenage years - isn't worried about Harlow hitting her terrible teens and has insisted she will adapt her parenting to suit the youngster's behaviour and attitude.

Asked how she will discipline her children, the former wild child said: ''It depends on how old she is. If she's 13, of course I will [set rules]. I'm going to have to figure it out as it happens.''

She added: ''I will have to see how I'm going to be when they're teenagers, but I think it also depends on who they end up being. I don't believe in black-and-white parenting.

''I believe in seeing who your kids are. I have very different kids; I handle them differently now. So that's something I am really going to have to wait and see.''