Demi Moore feels like a five-year-old child.

The 47-year-old actress - who has three daughters, Rumer, 21, Scout, 18 and 16-year-old Tallulah Belle with her ex-husband Bruce Willis - often forgets her age and thinks of herself as a young school girl.

She said: "I pretty much think of myself as like still being about five. Maybe that's why my twitter picture is of me at five."

Demi doesn't follow any strict beauty regimes to help keep her looking young and believes her childlike behaviour and willingness to smile and laugh help her stay youthful.

Speaking at a press conference, she told "I don't know if there is any particular secret to staying youthful. I think that laughter and smiling are one of the best antidotes to aging that you could possibly have."

The actress - who is married to 32-year-old actor Ashton Kutcher - feels very "privileged" with her life and works hard to make sure her children have her "positive perspective" everyday.

She said: "I feel like I have the fortune of privilege, particularly as it relates, say, to my children. I've always really tried to keep a positive perspective of what's valuable. that who you are isn't the stuff you have."

Demi recently starred in new movie 'The Joneses' - which is about a picture-perfect suburban - where she starred alongside the "extremely talented" Miley Cyrus, the daughter of country singer Billy Ray Cyrus.

She added: "I think she's extremely talented. This role is going to be really good for her. I think she'll do an amazing job. She clearly comes from a really solid family, which I think really shows."