Celia first met Hockney in Los Angeles in 1964. She is most famously represented in Hockney's large double portrait Mr and Mrs Clark and Percy, 1970-1 (Tate Gallery T01269). With her husband Ossie Clark she was at the top of the fashion industry in London in the 'Swinging Sixties'. Clark designed clothes using Birtwell's textile designs, and sold them from the shop Quorum in Chelsea's King's Road.
David Hockney: A Retrospective, exhibition catalogue, Los Angeles County Museum of Art, Los Angeles 1988, pp.50-1