Nicole Richie doesn't give her sister Sofia style advice.

The 35-year-old beauty is renowned for her fashion sense but she insists her favoured look is very different from her 18-year-old model sibling so they don't swap clothes or even tips.

She said: ''I'm very particular about my clothes. We have different styles.

''I don't know if I've given her any [style advice].''

But one area in which Nicole - who has kids Harlow, nine, and Sparrow, seven, with husband Joel Madden - could offer advice is on having healthy hair.

After years of dying her locks various different colours, the former 'Simple Life' star is now adopting a minimal approach and ''doing nothing'' with her tresses in order to get them back into good condition.

She told People magazine: ''Right now, I'm doing nothing [with my hair].

''I'm doing leave in conditioner, coconut oil and [that's it].

''I stopped straightening it--I was straightening it for a long time and I stopped--and basically stopped colouring it and just left it alone.''

And now she's getting older, Nicole doesn't want to let her hair grow too long and has given her locks a limit.

She said: ''I'm not trying to get any longer than my shoulders. I'm 35, let's be honest, so I don't really have that far to go.''

If Nicole does decide to give Sofia any fashion advice, she's likely to tell the teenager to splash out on turtlenecks as she recently spoke of her love of the versatile garments.

She said: ''I like the turtleneck style and then I just layer summer dresses or even jumpsuits on top.''