Cameron Diaz surprised herself by writing 'The Body Book'.

She told the Mail on Sunday newspaper's You magazine: "I never imagined I could create a book, let alone one this big. Because I am not that person.

"I am an actor - I don't produce, I don't direct, I have a very short attention span and I have progressed my career by listening to my intuition. I would think, 'What shall I do next?' and pick something that gave me that gut reaction.

"But then two years ago I had this absolute moment when it came to me that I had to do this book because nobody else was going to do it. I had to find a way to share the knowledge that I have about my body at 41 - and I'd had at 21."

The 'Annie' star has been surprisingly blunt in the book, discussing many intimate and sometimes embarrassing issues, including her teenage acne.

She added: "I think that for a young person, having bad skin is a real issue because your face is the first thing people look at when they meet you.

"So I wrote the book for my 16-year-old self, who I look back on and think, 'Why didn't I know these things then?' "