The 44-year-old actress, who is married to 29-year-old hunk Ashton Kutcher, said that the majority of good roles in Tinseltown go to women under the age of 30.
In her hey-day, Demi secured big money roles in films such as 'Indecent Proposal' and 'Ghost', but she claims that the work has dried up as she has got older.
Demi said: "It's been a challenging few years, being the age I am. Almost to the point where I felt like, well, they don't know what to do with me. I am not 20. Not 30.
"There aren't many good roles for women over 40. A lot of them don't have much substance, other than being someone's mother or wife.
"If we are told we are not valuable once we hit 30, it's a problem. We all have more to give."
