They've filled London's famous Royal Albert Hall to the rafters, packed out New York's Carnegie Hall and Sydney Opera House, and played sell-out concert around the world. Now Britain's most unusual orchestra is facing its biggest challenge, China.

The Ukulele Orchestra of Great Britain was on Friday rehearsing in London in preparation for its first ever tour of China, with four concerts scheduled Beijing, Shanghai, Chongqing and Hong Kong.

Forget trumpets, trombones, violins and violas, the eight-strong orchestra rely on the humble four-stringed ukulele.

The sounds created by those four strings have brought audiences to their feet, with standing ovations and cries for more.

In their extensive repertoire, the orchestra has a collect of songs written especially for the ukulele, as well as classical favourites and big-band musicals.

The orchestra's tour starts with a debut concert on Oct. 5 at Sha Tin Town Hall in Hong Kong. They then head for a concert on Oct. 7 at Chongqing Tiandi Theater. On Oct. 9 they perform at the Shanghai Symphony Hall. Three days later, on Oct. 12, the orchestra's final concert is at The Orange, Taikoo Li Sanlitun in Beijing.

The tour in China will be shadowed by a television crew, filming a documentary, and orchestra members will also be attending a number of workshops in the hope of introducing Chinese people to the instrument.

The orchestra's belief is any genre of music can be played on the ukulele, whether it is classical, post-punk, rock-n-roll or foot-tapping golden oldies.

The formula works, and the Ukulele Orchestra of Great Britain has been delighting audiences, raising the roof, selling out performances, and receiving standing ovations since 1985.

The orchestra, celebrated for its rapport with audiences, is eight performers, eight ukuleles, eight voices, with no gimmicks, no stage set, props or scenery, no fireworks, no special effects, no light show and no dancers.

Yet, millions have become instant fans of the orchestra, fuelled by catchy, emotive, stomping and toe tapping tunes, banter and wit and comedy.

The orchestra always sits in chamber group format, dressed in formal evening wear, regardless of the time of day or the venue.

As an orchestra spokesman commented: "You may never think about music in the same way once you've been exposed to the ukes."

The Orchestra is credited with spawning thousands of ukulele bands and orchestras across the world, popularising a cheap, easy to learn instrument.

Orchestra founder member Richie Williams, born near Liverpool, said: "We are all looking forward to our tour of China, all of us are eager to see the reaction of Chinese audiences to our music. What is incredible is around 90 percent of the ukuleles played these days are made in China and exported. Maybe our visit will create a string of ukulele bands in China."

Williams started playing the guitar as a young teenager and joined a number of pop groups in Liverpool from the age of 16, later becoming a professional musician.

In the 1980s George Hinchcliffe, the orchestra's leader, was staying with Williams and was invited to attempt to play a plastic ukulele with two of the four strings missing.

"George managed to get a tune out of the uke and it really started then. George came up with the idea of a ukulele orchestra and the rest, as they say, is history," said Williams.