Although she officially retired at the end of 1958, when she was still in her 30s, her aficionados have remained as loyal to her as Chan's following. She has emerged three times in the past four decades to raise money for charity, and people have flocked to hear her: in her comeback in 1987, she raised $12 million for her foundation.

Her most recent appearance was last year at the Cultural Centre on November 11 - Remembrance Day, appropriately enough - and she insists that that was definitely her final one.

Does she mean it? She laughs. Sitting in her Kowloon home, surrounded by flowers and portraits of the family for whom she gave up a career, she is like a delightfully approachable royal. 'Everybody asks me this. But now I'm old and the children say: 'Mummy, you promised you wouldn't do it again.' I feel very happy that I can do it and I enjoy it, but it's tough. There are fewer and fewer people around to do the costumes, the set, the make-up.' She started singing as a child, and it was soon apparent she had a gift which required nurturing. 'So my mother, who was very, very important to me, took me to opera school. At day I went to normal school, at night to opera school.' By the time she was 11, she had begun to play adult roles; the arrival of the Japanese in Hong Kong meant that she grew up quickly in real life, too. She has always been recognised as a woman who can convey heart-breaking emotion - on stage, she could cry at the snap of a finger - and she says that what she saw during the occupation deepened her performances. Her vocal style, as she describes it, was an ability 'to go all the way up to heaven and all the way down to hell'.

In 1950, she launched her film career. Her first film was called Not Getting Married, a title which, it would later turn out, was mildly ironic since it was the marital state which ended her stage and screen appearances. In the meantime, the magazine The Voice of Entertainment conducted a popularity poll in 1952 in which readers voted her the queen of the Cantonese opera.

She appeared in more than 100 films but it was the stage which remained her first love.

'With opera, there is interaction,' she says. 'The audience laughs and cries with you and you do it all at once, you let the emotions flow. The movies are hard, they're done in pieces, but I had to do them because at first it was something new and then, when I became famous, I couldn't refuse. In 1958, my last year, I spent 18 straight hours a day working.' And then she married. She met Dr Raymond Yang King-wong, who later became a heart specialist, through Lee who had decided to play match-maker. After Fong finished her last film, Butterfly Lovers, the couple flew to England - a 40-hour journey in those days - on December 22, 1958 (she is most precise about all the dates), and they were married on January 7, 1959. 'Then I started my new life as a housewife and a mother. I had seven children, four of my own and three stepchildren, and I love them all. I was so busy with my husband and children that for 28 years I didn't sing one word.' There is something in itself operatic about this sudden cessation. Indeed, there were lurid tales at the time that Dr Yang, cast in the role of Svengali, had given his new wife some potent medicine which removed her beautiful voice.

'My poor husband,' says Fong, laughing gently at the memory. 'Everybody hated him because he took the star away. We had a house at Castle Peak, near the mental hospital, and people thought that I was going up there as a patient. I'm not angry about it - people just said those things because they loved Fong Yim-fun - but now my friends are all very happy that there are no more rumours. And my husband encouraged me to come back.' But did she feel that she had become two people? 'Sometimes, you know, yes. In 1967, during the riots, we had no servants and I had to go to the markets to buy food and the people said: 'Look, it's Fong Yim-fun,' and I felt very happy. I was Mrs Yang and Fong Yim-fun. Sometimes my children see my old movies on TV and say: 'Mummy, they're so funny.' They don't understand them.' Dr Yang retired in 1986 and Lee suggested a comeback concert for the Kwan Fong foundation, which helps the poor and the elderly, the following year. That night, Fong sang at the old Lee Theatre where almost 30 years earlier she had performed in public for the last time in front of her future husband.

'I practised for about three or four months. And, it's funny, the first time I began to sing, it was still the same. My voice hadn't changed at all.'