Her salacious blog about her time as a high-class call-girl formed the basis of the money-spinning Belle de Jour books, and was sensationally challenged in a legal case brought by her ex-boyfriend who said she had never worked as an escort. But now author Brooke Magnanti has released a photograph of herself dressed in racy lingerie and posing seductively, saying it will form the basis of an extraordinary court case in which she will aim to prove she worked as a prostitute. Former lover Owen Morris – known only as The Boy in the books – is suing Dr Magnanti for defamation and breach of privacy, claiming her books destroyed his RAF career and saying he does not believe she worked as a call girl. Scroll down for video . The picture and advert Brooke Magnanti says will prove she worked as a call girl after her former lover said claims she was a prostitute were false . But this week it emerged that Dr Magnanti, 39, is to counter-sue for libel, and is likely to use the photo from the archived page of an escort website Alphababes from October 2003 as evidence of her work as a prostitute. The advert gives her name as Taro – a reference to a restaurant mentioned in her book – and states: 'Check out the pictures of our new addition, a super intelligent petite blonde Taro who is currently studying for her PhD and can provide all the services.' Dr Magnanti – whose books spawned the TV drama Secret Diary Of A Call Girl starring Billie Piper – also has photos of what she claims are bank statements showing payments made by alleged clients of £240 and £260 in October 2003. In 2013, The Mail on Sunday revealed Mr Morris was suing the author, claiming she could not have been a prostitute while they were in a relationship because she was typically clad in 'cute second-hand jumpers' rather than sexy outfits. Dr Magnanti, 39, is to counter-sue for libel, and is likely to use the photo from the archived page of an escort website Alphababes from October 2003 as evidence of her work as a prostitute which gives her name as Taro . Her salacious blog about her time as a high-class call-girl formed the basis of the money-spinning Belle de Jour books . The books about Dr Magnanti's life were later turned into an ITV2 series Secret Diary of a Call Girl starring Billie Piper (right) But Dr Magnanti has hit back with photographs of her wearing a silk red top and a photo of her at Henley Regatta wearing an Austin Reed jacket and a bracelet bought for her by a client. She claims to have an appointment book detailing her clients, as well as Mr Morris's diary in which he allegedly writes about his shock of finding out about her work in the sex trade. On her Belle de Jour blog she has outlined her case, saying Mr Morris's claims were an attack on her integrity. 'When the case goes to trial, I will have to present evidence that I was a sex worker. Starting with this – an archive.org snap of my first escorting ad from October 2003. Readers of the first book may recall this was the session with the grumpy photographer I wrote about. As I have often said, it was that experience – being made to wear terrible lingerie, awkward poses, all the rest – that first made me think, 'Hey, I should be blogging this.' ' In Secret Diary Of A Call Girl, Billie Piper plays Belle, an upmarket London call girl who keeps her profession secret from her family . The couple met in Sheffield in 2001, while Dr Magnanti was studying for her PhD in forensic science. She began writing anonymously as Belle de Jour in 2003 and, in November 2009, outed herself in a newspaper interview. The couple had split earlier that year. In August 2013, The Mail on Sunday revealed Mr Morris would be suing Dr Magnanti. He said: 'The Belle de Jour myth has ruined me and rendered me unemployable. The private lives of me, my family and friends were not only used without my knowledge or consent, but twisted and darkened. I am suing her because I want to stop Brooke destroying my life further.' In a statement, Dr Magnanti said: 'I can confirm a counter-claim has been lodged. 'I have been advised by my QC to offer no further comment pending the resolution of this litigation.' If the case goes ahead, it is believed it will be the first time a woman has sued for defamation for suggestions she was not a prostitute. Last night, Mr Morris did not respond to requests for comment. The case against Dr Magnanti is set to be heard in June. Dr Magnanti's story was sensationally challenged in a legal case brought by her ex-boyfriend who said she had never worked as an escort but another lover has backed her claim . Rowing coach Nick Wilde, 45, is known in the books as main character ‘N’, one of Belle’s best friends and former partners. He confirmed Dr Magnanti told him she was a prostitute – but said details of her books were exaggerated or deliberately altered to protect individuals she knew. ‘I have read the books and I’m familiar with N, who is based on me,’ he said. ‘I know N is an amalgam of characters and that there are things the character said that I never said and events he attended that I was at. 'There are also things I said and places where I was that are attributed to other people.’ He said that Brooke did confess to him that she was a prostitute and he is astonished at the suggestion that she was not. ‘She told me she was a prostitute and I believe that,’ Nick says. ‘Of course, I have no proof one way or another, because obviously I wasn’t there when she did it and I never lived with her. 'But she didn’t throw money around, not that I could see – she wasn’t exactly turning up at the pub in a Bentley.’ Nick, who has had no contact with Brooke for six years, said he believes the books are fiction with  a basis in reality. ‘Characters in the book are based on people. There is truth in it, but where the line is of who is real, who is not, I can’t tell you. Time, place and context are all mixed up. ‘N is said to have had a threesome, but I always say if I was supposed  to have had half as much fun as N, it would be great.’
Brooke Magnanti's blog about her time as a high-class call-girl was the basis for Belle de Jour books . But she was challenged in court by her ex-boyfriend who claimed she never worked as an escort . Owen Morris said in 2013 she couldn't be a prostitute because she wore 'cute jumpers' not sexy outfits . Now Dr Magnanti has released a racy picture of herself as proof as she prepares to counter-sue .