Julia Roberts takes beauty tips from her late grandfather.

The 'Pretty Woman' actress - who is famed for her mega-watt smile - says one of the best bits of advice she ever received from him was to brush her teeth with baking soda.

The mother-of-three said: ''I brush [my teeth] with baking soda. My grandfather would put a big heaping mound of it on his toothbrush. He had only one cavity in his entire life.''

Julia - who is married to cameraman DANNY MODER - says she doesn't really have any other beauty regime as she's too busy to spend lots of time on it.

She told America's InStyle magazine: ''Sometimes that's all I do as far as a regimen goes. Look, I'm happy if I have on moisturiser and ChapStick! When you're dressing three people besides yourself, something has to fall away. I've learned to always have a big pair of dark sunglasses within arm's reach before going out.''

The 44-year-old beauty also says it's unlikely she will have plastic surgery in the future, saying: ''I'm pro whatever works for you. For me, at this point, I'm clinging to my good genes and lots of hugs and kisses from my husband.''