She was famously portrayed by Billie Piper.
But now she's tired of hiding behind her famous pseudonym, Belle de Jour.
And in a shock move she's come forward and identified herself as Dr Brooke Magnanti, a research scientist from Bristol.
According to The Metro, Dr Magnanti, a specialist in developmental neurotoxicology and cancer epidemiology at St Michael's Hospital in Bristol, announced who she was on the very same blog that made her famous.
She wrote: "Anonymity is just too difficult. I supp
ose I always thought that the part of my life I wrote about would fade away, that I could stick it in a box and move on, totally separate it from the 'real me'."
She became a call girl shortly after she'd completed her PhD when money was tight.
She blogged about her time as a high-class prostitute, gaining notoriety and book deals in the process, leading to them being made into the ITV series, Belle de Jour: Diary Of A London Call Girl, with Billie in the lead role.
Dr Magnanti has said she revealed who she is because life was 'no fun' and she 'couldn't even go to her own book launch party'.
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