LOOKING like a water-breathing nymph, Keira Knightley is actually surrounded by photographers and lighting experts on all sides in this behind-the-scenes submarine picture. The photograph of the actress, as well as those of presenter Myleene Klass, comedian Matt Lucas and actress Sharon Stone were taken at a specially built tank at Pinewood Studios. The images are included in a forthcoming exhibition about how such shots are created, which takes place in October. Holding 1.2 million litres of water, the tank is the only one of its kind in the world, and has been used to shoot sequences in films including The Bourne Ultimatum, Casino Royale and Atonement. Phoebe Rudomino, who took the shots, said of Knightley: She was naturally very good. She was wearing a fairly heavy dress which made it hard but she was surrounded by safety divers and she did very well. The actress, 24, was filming to promote the charity Fresh2o, which aims to provide clean water to people. Rudomino added that the process of making an image was often less than glamorous. There may be gaffer tape holding a bikini together or divers hanging upside down to keep someone in a certain position but the viewer will only ever see the final polished shot, she said. Telegraph The exhibition, Water on the Lens, will be held at the Movieum of London on the Southbank throughout October. Telegraph