Actress Julia Roberts has vowed never to strip for a film role again - because it's not 'real' acting. The 40-year-old Oscar winner - who won legions of male fans after her role as a scantily-clad prostitute in Pretty Woman - believes actresses who shed their clothes for films are not staying true to their craft.

She tells OK! Magazine, "I wouldn't do nudity in a film. To act with my clothes on is a performance. To act with my clothes off is a documentary." The mother-of-three - who is mother to twins Hazel and Phinnaeus, three, and a six-month-old son, Henry - famously had to be coaxed into wearing a bikini for new film Charlie Wilson's War.

And she admits she's not too confident about her sex appeal these days: "I'm too tall to be a girl. I wouldn't call myself a woman. I'd say I'm somewhere between a chick and a broad."