During the day he is a cleaner who sweeps floors in offices. At night he plays the piano and dreams of performing at a concert. Lau Chi-ming, a 32-year-old mentally handicapped man, will get a chance to realise his dream next month when he gives his first solo piano performance with the Metropolitan Youth Orchestra of Hong Kong in a charity concert. The concert has been organised by the Hong Chi Association, an organisation dedicated to helping the mentally handicapped. Mr Lau has an IQ of between 50 and 69 - a score of between 90 and 110 is regarded as normal or average intelligence - and he cannot read music. But he has an amazing ability to play music just by listening to it. For instance, he learned to play Mozart's Piano Concerto No19 in F Major just by listening to the piece of music with a CD player. He simply memorised the 15-minute piece of music which fills 42 pages in print. 'I work from 7am to 5pm and I practise playing the piano for four hours after having dinner. I don't feel tired. I just want to play the piano. If I cannot play the piano, I will feel terrible and very sad,' Mr Lau said. Mr Lau's father discovered his son's talent for music when he was 13 and bought him an electronic piano the next year as a birthday gift. 'It is easier to play pop songs than classical music. Mozart's music is more difficult to play,' Mr Lau said. 'I like spending time in music shops and play electronic pianos there. I stay there for up to four hours. The shop assistants all know me and they like me a lot. I can do many sound effects with a song when I play the electronic piano.' Despite Mr Lau's passion and talent for music, he did not receive any formal training until recently. 'I used to play the piano with six fingers and now I play properly after my teacher taught me to.' Jenny Wong Wai, a Hong Chi Association volunteer who been teaching Mr Lau, said his achievements were beyond her expectations. Asked what he wished to make his first piano solo performance perfect, Mr Lau said: 'I want to dress in a tuxedo when I play the piano in concert. 'Just like Lang Lang ,' he said, referring to the 26-year-old Liaoning -born piano superstar. The Hong Chi Association is appealing for a sponsor to make Mr Lau's wish come true. Mr Lau will play at the Cultural Centre on January 13.