IN the United States Jon Cleary is billed as the Englishman who plays the music of New Orleans. In Europe, where he is an increasingly potent concert attraction, he is billed as coming from America. Tonight and tomorrow he is in Hongkong playing at the Jazz Club, and when Cleary sits down at the piano stool it's immediately obvious that exactly where he comes from doesn't matter at all. Cleary is an acknowledged master of the funky style of New Orleans piano defined by artists such as Dr John, James Booker, Allen Toussaint and Professor Longhair. Cleary takes up where Professor Longhair, who Toussaint once called ''the Bach of rock'' left off. He has immersed himself deeply in the tradition, but is intent on adding something of his own to the New Orleans musical gumbo. ''I've always loved black American music, not because it's black and not because it's American but because there's something very soulful about it which I can feel,'' says Cleary. Having spent his teens in a small English village soaking up the music from records and developing a considerable talent for playing the guitar, at the age of 17 Cleary took off for New Orleans to try to get closer to the music at source. On arrival in the city he found himself a job repainting the Maple Leaf Bar, where the late James Booker had a regular gig, and rented an old bargeboard house with a piano in it. Having left his guitar behind in England he switched instruments and very quickly found himself standing in for Booker on occasions when for one reason or another the great man didn't show up. His reputation spread, and soon Cleary was seriously in demand around the New Orleans bars. The city's musical community is close-knit, and he has now worked with most of the acknowledged greats of New Orleans rhythm and blues who are still alive and performing. These include Dr John, Walter ''Wolfman'' Washington, and the bass player George Porter Jr who is one of the musicians featured on Cleary's debut album, Alligator Lips and Dirty Rice. One musician with whom Cleary has established a particularly close connection is Dr John, who also started out on guitar before becoming better known as a pianist. The two now perform as a duo, alternating between the two instruments. ''Dr John switched to piano after a dispute over payment for a gig,'' said Cleary. ''Somebody shot him and he lost the tip of one finger of his left hand, which makes guitar a bit difficult for him.'' Much as he loves the city, Cleary has also had some alarming experiences in New Orleans. He recalls waking up in his bedroom one evening to find himself looking at the wrong end of a shotgun. ''There were a couple of these guys and the one with the gun said something about blowing my brains out. I managed to jump out of the window and get out of there. In the end all they got was my hat and a battered old ghetto blaster that didn't work anyway,'' he said. Although his English origins make him, in some respects, an exotic figure, in New Orleans they have apparently never been a barrier to acceptance by musicians or audiences. ''People know if you're playing the music right. There are a lot of poor imitators but if you're playing it in a way that gets them in the hips and in the groin and in the soul, that's all that matters,'' said Cleary. Race is nevertheless an issue in the city. It is, Cleary points out, only a couple of years since the Klu Klux Klan were taken out of the phone book. ''They used to be right there in the yellow pages. You'd look under 'K' and there would be Koo-Koo the clown and the Klan.'' Cleary, who has just completed the latest in a series of successful tours of Australia, will be performing solo at the Jazz Club playing a selection of his own compositions and a variety of other New Orleans style pieces on which he puts his own distinctive stamp. Don't miss him.