For Absolut Secret, at London's Royal College of Art, is the ultimate lucky dip.

The show consists of 3,000 unsigned postcards, all costing £30, of which at least 300 have been painted by a famous hand.

Well-known artists from the US and the UK, former RCA students and current college pupils have come together to make the cards.

But instead of putting their name on the front, it is written on the back. Their identity remains a secret until the buyer returns a few days later.

In previous years, artists have included Frank Auerbach, Peter Blake, Raymond Briggs, Claes Oldenburg, David Bowie and Paul Huxlley.

This year, Turner Prize winner Chris Olfili, creator of the new Oscar Wilde memorial Maggie Hambling and jazz musician George Melly are also in the pack.

Absolut Secret goes on for three days but queues start early and stretch around the block.

Its aim is to raise money in support of the Fine Art students at the RCA. Last year, £70,000 was raised and organisers are now hoping for more.

The idea was coined jointly by an RCA student and its Fine Art Development officer Susie Allen.

Sponsorship was found in 1994 from the Absolut vodka company and the first 400 cards went on sale. The media attention and the success of following shows have led to the current mammoth enterprise.

Frank Auerbach and Peter Blake were the first big names to lend their support in the early days. Now, enlisting the talents of many more is no problem.

In fact, says organiser Ms Allen, they even call to offer their services.

"The attraction of the show for established artists is that it gives them the chance to let their hair down, experiment and help struggling new talent."

And such is the subsequent prestige of the show that up-and-coming artists list their own involvement on CVs.

But even if people cannot get to the show on the first day, Ms Allen is keen to stress that the pickings can still be rich right up until the end.

"Last year one of the very last cards was by a famous artist and the man who bought it was speechless with joy - he had little money and the artist turned out to be his favourite."

Some of the cards are worth a pretty penny. An Auerbach would, for example, be worth around £30,000.

However, Susie Allen and all involved, do not like to dwell too much on that side of things. Ultimately they want people to buy a piece because they love it.

They also want to emphasis that Absolut Secret is vibrant, fun and accessible - just like great art should be.

This year a parallel exhibition will be held at the Davis McKee gallery in New York on 16 December. Susie Allen hopes that with more than 600 UK and US artists taking part, "it could be the largest and most prestigious transatlantic show ever".

Absolut Secret takes place from 3 - 6 December at the Royal College of Art in Kensington Gore, London.

Time: 3 - 4 December 0800 - 1900 and 5 - 6 December 1000 - 1700.