Julia Roberts takes beauty tips from her late grandfather and says one of the best bits of advice she ever received from him was to brush her teeth with baking soda.

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."