Julia Roberts: "I brush my teeth with baking soda"

Julia Roberts has opened up about beauty routines and plastic surgery in a new interview.

Pretty Woman star Julia Roberts stays beautiful at 44 thanks to an unusual tip from her grandfather.

She told InStyle magazine of her famous smile:

"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 Roberts and husband Danny Moder at the Heal The Bay's Bring Back The Beach Fundraiser in May 2012. Source: Getty

She added of brushing her pearly whites:

"Sometimes that’s all I do as far as a regimen goes. Look, I’m happy if I have on moisturizer and ChapStick!"

The mother of three explained:

"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."

Roberts said she hopes to steer clear of beauty treatments like plastic surgery and Botox.

She said she is 'pro whatever works for you', but added:

"For me, at this point, I’m clinging to my good genes and lots of hugs and kisses from my husband."