Celebrity thrives on controversy, especially in moments of heightened national, racial and moral tension.

In 2015, furore surrounded the potential prosecution of actor Amber Heard – then married to Johnny Depp – for illegally bringing the couple’s pet dogs into Australia.

Rapper Snoop Dogg was denied entry in 2007 due to firearms and drugs convictions in the United States, and a public petition in 2014 again sought to withdraw the provocative performer's Australian visa.

But a century earlier, another American celebrity was granted privileged permission to visit Australia. His treatment was particularly unusual because he was an African-American sportsman, and his request to enter the country came at the height of the White Australia policy.

Jack Johnson, 'coloured pugilist'

Described in the language of the time as a 'coloured pugilist', Jack Johnson was travelling to Sydney in 1908 to contest the World Heavyweight Boxing Championship.

Born in Galveston, Texas, Johnson held the title of 'Coloured Champion of the World'. Previously coached by Melbourne-born boxer Dan Creedon, he had visited Sydney and Melbourne for fights in 1907.

But to return to Australia, Johnson required an exemption from the nation’s notorious dictation test, which was designed to exclude non-white 'aliens'.

A six-month exemption was authorised by Atlee Hunt, head of the Department of External Affairs. Hunt had been instrumental in creating Australia's controversial Immigration Restriction Act, so his personal intervention was significant.

The fight

There was much more at stake than a temporary immigration exemption. Johnson’s opponent was Canadian-born Tommy Burns, billed as the 'Champion of the World'.

Like most white boxers, Burns maintained a 'colour line' in North America, refusing to contest his title against African-American challengers. But a huge fee convinced Burns to fight Johnson – not in America, but in Sydney. For local audiences, the question was not just who would win, but what it would mean for 'White Australia'.

The bout took place on 26 December 1908. Held at a new 20,000-seat venue, The Stadium, the event was packed beyond capacity.

Over 14 rounds, Johnson completely outclassed his opponent. Local police eventually halted the contest, apparently to prevent the white crowd from rioting as much as to protect Burns from further injury.

Johnson was declared the winner, becoming the world's first non-white heavyweight champion.

The Great White Hope and Great White Fleet

Another American celebrity was in the crowd that day: popular author Jack London. Appalled by the result of the fight, London called for a 'great white hope' who would regain the championship from Johnson.

Although his phrase became infamous, it is rarely connected with another celebrated group of American visitors – the 'Great White Fleet'.

Just four months earlier, in August 1908, 16 white-painted battleships of the US Navy had entered Sydney Harbour to a tumultuous welcome. Seen as a counter to Japanese naval power, these potent visitors helped proponents of White Australia draw yet another colour line.