Mila Kunis and Ashton Kutcher only bathe their children when they see dirt on them

Speaking in the latest 'Armchair Expert' podcast, co-hosts Dax Shepard and Monica Padman discussed the frequency in which they wash.

When the 'CHIPS' star told Monica that she should "not be getting rid of the natural oil on your skin with a bar of soap every day, the 33-year-old podcast host replied: "I can't believe I am in the minority here of washing my whole body in the shower. Who taught you to not wash?"

The 'Bad Moms' star, 37, revealed that she hardly ever had a shower growing up as a child because they didn't have hot water at home.

Mila explained: "I didn't have hot water growing up as a child, so I didn't shower much anyway. But when I had children, I also didn't wash them every day. I wasn't that parent that bathed my newborns — ever."

Ashton, 43, added: "Now, here's the thing: If you can see the dirt on them, clean them. Otherwise, there's no point."

And the same principle applies to his own hygiene habits as he only cleans his armpits and crotch.

He explained: "I wash my armpits and my crotch daily, and nothing else ever. I got a bar of Lever 2000 that delivers every time. Nothing else."

However, the couple - who tied the knot in 2015 - do like to wash their faces after getting hot and sweaty at the gym.

Ashton said: "I do have a tendency to throw some water on my face after a workout to get all the salts out."

Mila added: "I do wash my face twice a day."