One is notorious Belle De Jour, who blogs about life as a prostitute.

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Piper, 29, also gained acclaim for ITV's Secret Diary of a Call Girl, in which she played the high-class London escort Belle de Jour.

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Brooke Magnanti, who now writes for London's Daily Telegraph, is a former call girl who wrote a blog of her life as a prostitute under the pseudonym Belle de Jour.

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