It is the first retrospective exhibition of his work that concentrates on his photography, not paintings.

Hockney is most famous for his paintings of swimming pools, but in 1964, when he settled in Los Angeles and painted his first swimming pool pictures, he also took his first Polaroids.

Curator Rheinold Misselbeck: 'This is the first retrospective of his work from the standpoint of his photography'

His interest began with the need to record detail for his paintings.

For his 1966 painting "Peter Getting Out of Nick's Pool", he took Polaroids of his lover Peter Scheslinger leaning over the bonnet of an old car.

But he developed an interest in the relationship between reality and the photographic image, which led him to create the famous photo collages of the 60s, 70s and 80s.

The exhibition came to Cardiff through the friendship between the previous director of the National Museums and Galleries of Wales, Colin Ford, and the artist.

Mark Evans of the NMGW said they are delighted to be staging the exhibition.

Hockney is Britain's most famous living artist

"This is the most representative exhibition of his photographic work that's ever been assembled," he said.

The exhibition in Cardiff spans 30 years of Hockney's work and features a huge range of the famous people who have gathered at his poolside.

But all the photographs - from Dennis Hopper in sports casual clothes to a portrait of Wayne Sleep in the nude - show people in natural, relaxed poses.

The exhibition moves from intimate collages of close friends to laser prints of visitors to his house in Hollywood, among them Billy Wilder and Annie Leibowitz.