The show begins its journey at the turn of the century, with Paul Poiret, who shared a taste for Orientalism and decoration with the painters Matisse and Dufy, as well as the creative director of the Ballets Russes. Along the way, the exhibition pays homage to Salvador Dali and the Surrealist fashion designer Elsa Schiaparelli, whose influence can still be seen today on designers as diverse as the milliner Philip Treacy and the Italian fashion house Moschino; and traces the link up to the present day when, it seems it is the fashion designers who lead the way, rather than the artists. It is no longer enough simply to design clothes. To have credibility and integrity, a designer has to make clothes either so weird and unwearable that they are called "art", or so conceptual that they are bought by galleries to be shown in glass cases. If all they want to do is sell clothes, they make commercial collections and open art "foundations", or sponsor art prizes.
The association with art and design rubs off on to the fashion label, while the fashion world can provide the necessary finance and glossy media attention to provide sponsorship for art exhibitions.
Last week at the designer shows in London, many of the offerings on the catwalks prompted the question: "Is it fashion or is it art?" Alexander McQueen's show included a live art happening with robot arms and spray- paint. Hussein Chalayan's conceptual show was a carefully choreographed one-off art piece, presented in an East End art gallery. Antonio Berardi's basketwork corset and skirt are like sculptures when taken off the body. And Antoni & Alison, who originally trained in textiles and fine art, used photography as the basis of their printed accessories and clothing, which are as much art as fashion.
As the Hayward's exhibition points out, the relationship between fashion designers and artists is nothing new. But during this decade the snobbery that for so long has kept the two worlds at paintbrush length from each other has been slowly ebbing away. We now have the annual Hugo Boss contemporary art and sculpture prize, sponsored by the German suit company. Then there is the Prada foundation, Miuccia Prada's contribution to the art world in the form of a gallery space that features two exhibitions a year. The next show, to open in November, is a one-woman show by the British artist Sam Taylor-Wood.
And, of course, when Mrs Prada decided to host a dinner for her British friends in London earlier this year, she did so at Damien Hirst's trendy restaurant.
Superficially, at least, it seems that fashion and art, cannot live without each other. Another designer who has long cultivated a relationship with the art world is Issey Miyake. While he has several pieces in Addressing the Twentieth Century, the Japanese designer is hosting his own exhibition, Issey Miyake Making Things, in Paris at the Cartier Foundation from 13 October until 17 January. It celebrates the designer's work over the past 10 years. Included in the installations is "Jumping", a sequence of 25 dresses that dance on their own; pieces by Miyake's four guest artists, who have each used the designer's "Pleats Please" collection of tops, skirts and trousers as limited-edition canvases for their work; and a reflection on clothes for the 21st century, using clothes recycled by Miyake. Next season sees the last guest artist in the series: Cai Guo- Qiang is a Chinese conceptual artist who works with gunpowder and controlled explosions.
Also included in the Hayward show is work by Comme des Garcons. The label's designer, Rei Kawakubo, uses clothes to push the boundaries of the body and our perceptions of it. For spring-summer 1997, she gave her clothes growths and lumps and bumps that made the wearer look deformed.
On the catwalk, they were seen as weird and warped. But in the Hayward they can be viewed as sculpture. Perhaps Kawakubo may be better understood as an artist than as a fashion designer. If you would like to see more proof, her costumes can also be seen this week at the Barbican. Her padded clothing sculptures are worn by the dancers performing Merce Cunningham's Scenario, in a true pairing of art and fashion.
`Addressing the Twentieth Century: 100 Years of Art and Fashion', 8 Oct-11 Jan 1999 at the Hayward Gallery; tickets pounds 6. `Issey Miyake Making Things', 13 Oct-17 Jan 1999 at Cartier Foundation for Contemporary Art, 261 Boulevard Raspail, 74014 Paris. Prada Foundation, Via Spartaco 8, Milan. Merce Cunningham Dance Company, Barbican Theatre, Silk Street, London EC2, 0171-638 8891