Prince Harry will launch the 2018 Invictus Games in Sydney on Wednesday and begin the official countdown to the Paralympic style tournament.
Harry will join Australia's prime minister Malcolm Turnbull and governor-general Sir Peter Cosgrove for the event marking 500 days to the start of the international championship for injured, wounded and sick military personnel and veterans.
All three figures will give speeches at Admiralty House, the official residence of the governor-general, and members of Australia's 2017 Invictus Games squad will be among the invited audience.
Next year, more than 500 competitors from 17 nations will take part in 11 adaptive sports across Greater Sydney, including Sydney Olympic Park and on and around the city's harbour.
Sailing has been introduced for the 2018 Invictus Games and Harry will watch a demonstration of the sport in Sydney Harbour from a rib on the water with the iconic Sydney Opera House in the background.
He will later go on a walkabout, meeting Australians along the harbour-side before watching demonstrations of adaptive sports for people with disabilities, from wheelchair rugby and sitting volleyball to wheelchair basketball.
The Invictus Games, which this year will be staged in Toronto, Canada, were founded by the prince and first held in London in 2014 to great acclaim from the competitors and spectators.
Harry is patron of the Invictus Games Foundation, which oversees the delivery of the tournament which was hosted by Orlando, Florida in 2016.