By Sandra Rose  | 

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Ashton Kutcher and Mila Kunis recently revealed their dirty little secret -- they don't bathe themselves or their children for days on end.

Jake Gyllenhaal also revealed he doesn't believe bathing every day is "necessary".

The 40-year-old actor believes water dries his skin and he has to moisturize more often.

He says not bathing for days is "helpful for skin maintenance" to allow the body to "naturally clean" itself before taking a bath.

"More and more I find bathing to be less necessary, at times," he told Vanity Fair magazine.

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The Relic star made the comments after a debate about cleanliness was sparked by Hollywood power couple Mila Kunis and Ashton Kutcher, who recently admitted they don't bathe their children until they "see dirt" on them.

Kunis and Kutcher revealed their hygiene practices during an appearance on the Armchair Expert podcast.

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

"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."

Body odor usually doesn't occur in children because their underarm sweat glands don't develop until puberty.

Sweat is usually odorless in adults. Body odor is caused by bacteria feasting on dead skin and the compounds in sweat.

Soap and water temporarily decreases bacterial colonies in the underarms.

Question: How often do you shower or bathe?

A. Once a day
B. Twice a day
C. Once a week
D. Twice a week
E. When I smell myself