Hunt was the creative founder partner of TBWA\Hunt Lascaris in South Africa when the agency started in 1983. He recently relocated to TBWA's New York headquarters in April 2003 to take on the role of worldwide creative director.
Terry Savage, chief executive of the festival, said: "We've watched John's increasing success over the years. The outstanding work TBWA has created under his leadership confirmed our view that the time was right for him to take on the role as jury president in 2005."
TBWA won 28 Lions across all categories at the 2004 International Advertising Festival, as well as winning Agency Of The Year and Lion for Excellence in Music for the PlayStation2 ad "mountain".
"Cannes has evolved to be the pre-eminent global showcase of creative advertising," Hunt said. "To be asked to be jury president is a terrific honour."
Hunt was also involved in Nelson Mandela's ANC election campaign in 1993 and was the first working creative to be elected to the South African Advertising Hall of Fame.
Cannes Lions International Advertising Festival was bought by Emap in August in a £52.5m. The event, first held in 1954, was put up for sale at the beginning of July by the Hatchuel family, who ran the festival as a privately owned company.
The sale of the festival, which had operating profits of £7m this year, was reported to have come about after a disagreement between its former owner Roger Hatchuel, and his son, Romain.
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