SYDNEY - AUSTRALIAN Olympic diver Matthew Mitcham, the only openly gay medal winner at the Beijing games, was chosen on Friday to lead Sydney's gay and lesbian Mardi Gras parade and is expected to get a hero's reception from the crowd.

Included in the parade will be a special tribute to assassinated American politician Harvey Milk, the first openly gay person elected to office in California.

Thousands of spectators are expected to line the route of the parade, which kicks off at 7.45pm (AEDT) on Saturday from Hyde Park in the centre of Sydney.

The parade, which started as a protest march for human rights by the Australian gay and lesbian community in 1978, is now in its 31st year. -- AAP