The 47-year-old actress is still looking very youthful, but she does her best to keep on top of any tell-tale signs of ageing.
She admitted: "I don`t dye my hair, but I do have a few greyhairs that I pluck out."
The sexy star - who is married to actor Ashton Kutcher, who, at 32, is 15 years younger than his wife - also revealed she hates working out but has taken up Bikram yoga, which is performed in extremely high temperatures, and is finding it works wonders for her figure.
She explained: "I`d love to say that I exercise a lot but I don`t.
"Although Ashton and I have started Bikram yoga. You`re sweating so badly, you realise very quickly that no one cares what you look like, you`re all just trying to get through the 90 minutes."
Demi admits her relaxed attitude to her appearance is relatively recent for her, but she feels much happier since she started worrying less about her looks.
She said: "I spent a good part of my early career feeling my external was a measure of value and got obsessive compulsive.
"I dieted, weighed my food and was generally a lunatic. It was only once I stepped away and realised you need to improve from the inside out that I got closer to the body I always wanted."