Los Angeles - Cameron Diaz drinks a litre of water to make her go to the toilet each morning.
The health conscious star cleans her teeth as soon as she wakes up before gulping an entire bottle of water in one, as she believes it is good for her body.
Appearing with US TV's Dr Oz, she showed him her water bottle and explained: "This is the best way for me to go poop in the morning. Water wakes you up.
"First, I brush my teeth because I don't want to swallow all the bacteria in my teeth from the night before. So I make sure that's gone and then..."
Cameron, 41, is currently promoting The Body Book which she has written about maintaining a healthy body, and includes a whole chapter on bowel movements, which she insists is a very important topic.
She added: "Let's talk about poop, baby! Yes, you heard me right. Listen, it's a natural and necessary part of being human. Now I know that some people don't like talking about their bowel movements but here's why I'm talking about it: because your poop is a key indicator of your overall health."
Youthful-looking Cameron has also recently said anybody can have a figure like hers if they learn how to take care of themselves properly.
She said: "Everybody can have my body. Everybody can have exactly my body but it is going to look different. It’s about having the internal knowledge of that body and teaming it with the proper nutrition and fitness to have the body you're supposed to have."