Brooke Shields says being famous is like a "drug".

The 44-year-old beauty spent much of her childhood acting and modelling and while she enjoyed it, she will never let her two daughters, Rowan, six, and three-year-old Grier, follow in her footsteps because she also knows the pitfalls.

She said: "It's a high like you can't imagine. It's like a drug.

"But no, I don't want them involved. Every day you're told what you are not: You're not short enough, you're not thin enough, you're not pretty enough. You're always losing out."

Brooke also revealed her heartache at watching her own mother suffer from Alzheimer's disease and the effect the illness - a form of dementia - has on her children.

She told the Ladies Home Journal magazine: "I've dealt with her alcoholism for years, but this is so new to me. I'm confident in my own mothering, I've been making all my own decisions for a long time, but after all these years, I want my mom.

"My oldest is uncomfortable because she knows more. One day she said, 'Mom, are you gonna be crazy like Toots when you grow up?' I was like, 'Oh, God.' "

But Brooke - who is married to television writer Chris Henchy - admits being a devoted working mother, wife and daughter can be quite challenging.

She said: "I'm greedy. We were walking to school yesterday and my daughter said, 'Mom, I want you to be a class mom.' I laughed in her sweet little face and said, 'You want me to be a class mom?' I said, 'I'm a classy mom. Isn't that enough?' "