Cooper, who was executive chef of the Goring hotel, London, for five years until earlier this year, will oversee the reopening of Julie's in September, following an extensive renovation nearly 50 years after the restaurant's launch.
When it opened in November 1969 with interior designer Julie Hodgess at its helm, the restaurant swiftly earned a reputation as a venue for celebrities and royalty. Over the years it became a regular haunt of the likes of Diana, Princess of Wales, Sir Paul McCartney and Kate Moss.
Although Hodgess sold the restaurant in 1972 to Tim and Cathy Herring, she will oversee the new-look interior, which will retain the decadent feel of the original site with stained-glass windows, Gothic wood carvings and a honeycomb of small alcoves.
Cooper's menu of modern British cuisine will include glazed ox cheek and aged sirloin beef. He will be joined by the Herring's grandson, Ralph Herring, as chef de partie.
Cooper said: "I am excited to contribute to preserving and building upon the legacy of the restaurant, which cares about its neighbourhood. Julie's has always had a loyal following for its ambience and atmosphere, and it is my ambition for the restaurant to gain a reputation for great food."