YANG Man-shih - better known as Yonfan - just wants to talk about sex these days. In fact, it is a subject that is weighing rather heavily on the mind of the Hong Kong-based director. This is because his next project will take Hong Kong and international film-goers into a twilight world that few have ventured to before . . . a land of fantasy that no longer even exists. But, when cameras start rolling in Singapore in November for Bugis Street, the republic's once-infamous landmark will come to life again with its drug peddlers, prostitutes, gangsters, dai pai dongs and flamboyant transvestites. For Yonfan, it will be the realisation of part of a long-time dream. ''I've always wanted to make a trilogy of films with sexual themes. One would be the screen adaptation of Taiwanese author Bai Xinrong's novella Evil to which I have bought rights, another would be on transvestites and a third would take a different look at a lesbian relationship,'' he said. So when Singaporean producer Katy Yew approached Yonfan and good friend Sylvia Chang Ai-chia with a proposal on Bugis Street after watching the duo's latest offering, Conjugal Affairs, Yonfan jumped at the chance. Chang is currently in the US for the filming of an American production. ''I've made so many movies and I've never followed commercial trends. I've always followed my heart. When I heard of the project, I knew I had to do it even though I was about to start working on the Bai Xinrong film. But I knew this would not be on as large a scale as the former,'' he said. Financed by Singaporean backers, the US$2 million production will not focus on life in Bugis Street - which was demolished long ago - but on the sort of characters who gave life to it. Yonfan is admittedly intrigued by the often double lives of transvestites. ''Why are there so many transvestites in tropical countries? Do their families enjoy seeing them parading around as women?'' he asked rapidly. But far be it for Yonfan to churn out a commercial tale of down-trodden transvestites and lives of misery, or love and romance among transvestites and heterosexuals. ''It will be something different,'' he promised. ''It will be more about the people and human relationships and the tussle between the conventional and the non-conformists.'' The film will tell the story of a 17-year-old country girl whose job in a sleazy hotel near Bugis Street brings her into contact with the people who haunt the street. She meets Drago, a Singaporean transvestite who has spent some years abroad and whose philosophy and ''totally emancipated way of thinking'' helps her see that her conservative outlook is a stumbling block to her dream of becoming an author. Of the old Bugis Street, Yonfan says: ''You could find everything there: people who wanted to be bizarre, people who wanted to make money . . . you could find mystery, tragedy and comedy. Very spicy and so amazing, it was unreal.'' The film will most likely star Singaporean transvestite Grego, a hairdresser and makeup artist although Yonfan initially had more international ambitions in mind. ''I had wanted to get John Lone for the part because the role of Drago is not one that any Hong Kong actor can play convincingly. But we have not made contact with him yet,'' said Yonfan. ''He probably will not be able to accept anyway because we are about to start filming soon. ''Eighty per cent of the film will be in English and because it is a film about Singapore, it will have its own flavour. If I can find locals to take the roles, I would definitely prefer them. Unless, of course, it is John Lone, who will be able to draw international attention. ''But Grego is very good. He's very flamboyant and outrageous. We've picked six Singaporean transvestites and transexuals for various roles. For the female lead, we're talking with Hiep Thi Le (of Heaven And Earth ). She's expressed her interest but we haven't come to an agreement because we are still working on the script. ''It is ambitious casting but this is not a Mandarin movie. I don't think it is going to be called a local Chinese production, yet you cannot say it is a Hollywood one because the production size is not as big. I would not want it to be categorised as such. I think it should be more artistic than entertaining.'' The ebullient director will also double as scriptwriter since he found no takers from any of the Singaporean scriptwriters he offered the job to. ''The subject can be very controversial and the local scriptwriters are more scared since they would have to stay on and face the music if it turns out to be controversial,'' he said. ''We approached several people but they all said that the project was 'too big' for them to handle.'' But they may be fears that are well-founded because already one cast member has fallen casualty to the publicity surrounding the new film. ''Sophia, one of the 'beauties' cast in the movie, was fired from her job the day after she made the newspapers. Apparently no one at her office knew she had had a sex change operation and when they found out they fired her. Katy [Yew] wrote a letter of protest to the Labour Department about that,'' Yonfan said. Being the scriptwriter as well has meant that the director has had to make lengthy stays in Singapore to do research and conduct in-depth interviews with ''beauties'' to gain a deeper understanding of their lives. Besides that, there was the usual scouting for suitable locations because the Singaporean Government pulled down the original Bugis Street in 1985 and rebuilt a replica two streets away - minus the ''beauties''. ''We found most places which we needed to use but just as we were about to apply for permits, the management of the new Bugis Street called up to offer us free rein on the new location,'' he said. Even so, Yonfan and producer Yew were rather doubtful. ''We told them it was too new, we wanted it the way it looked in the 60s and it would cost too much to make the buildings look old.'' The management brushed their worries aside by offering to pay for the dressing down of the new buildings, so the Bugis Street film crew will be literally camped there for two months. Only one question remained: Will there be explicit sex scenes? ''That is exactly the same question that the scriptwriters asked me,'' Yonfan laughed. ''They wanted to know how many sex scenes there would be, how many minutes each scene was, and whether there would be scenes of men making love to men . . . and I said, 'my god, are you asking questions for the government or are you writing a script for me?' ''But the answer is, I really don't know. There will be nudity and sex scenes - that is nothing in this day and age - but to what extent, I don't know. We'll have to go with the flow when the time comes. Being too explicit is not always good.''