Ashton Kutcher loves to urinate outside his house every morning - because he wants to feel closer to nature.

The Dude, Where's My Car? funnyman admits he likes to join his dogs when they empty their bladders in the morning outside the home he shares with his wife Demi Moore.

And he blames his weird toilet habit on his desire to bond with the earth and feel like a "caveman".

He says: "I pee outside, outside my house, in my yard. I usually start off my day by taking my dogs out. While they go, I go.

"That's probably my least appealing habit. I just feel like I'm connecting with nature, I bond and feel like caveman. Man, tents, cave, pee, bush."