Secret Diary of a Call Girl is a British drama television series that aired from 27 September 2007 to 22 March 2011 on ITV2, based on the blog and books by the pseudonymous Belle de Jour. It stars Billie Piper as Belle, a high-end call girl in London.

Brooke Magnanti is an American-born naturalised British former research scientist, blogger, and writer, who, until her identity was revealed in November 2009, was known by the pen name Belle de Jour. While completing her doctoral studies, between 2003 and 2004, Magnanti supplemented her income by working as a London call girl known by the working name Taro.