Prince Harry's double celebration

Prince Harry and Meghan Markle went public with their relationship at the Invictus Games in Toronto.
Prince Harry and Meghan Markle went public with their relationship at the Invictus Games in Toronto.

Prince Harry has cause for a double celebration this week.

The Duke of Sussex turns 34 on Saturday, which also marks exactly five weeks until he and the Duchess of Sussex kick off the Invictus Games for defence veterans in Sydney.

The week-long Games, which begin on October 20, will be a key plank of the royal newlyweds' schedule for their first major international tour to Australia, New Zealand, Tonga and Fiji.

They're set to arrive in Sydney on October 16, before visiting the central western NSW city of Dubbo, Melbourne and Fraser Island in southeast Queensland. They'll fly out of Australia for Fiji on October 23.

It's just over a year since Harry and Meghan sparked a global media frenzy as they made their first official public appearance together at the Invictus Games in Toronto, complete with hand-holding and the occasional sneaky kiss.

"Invictus carries very fond memories for them," royal commentator Richard Fitzwilliams told AAP.

More than 500 competitors from 18 nations will battle it out in 11 adaptive sports ranging from wheelchair rugby to swimming and athletics events at the Sydney Invictus Games.

Harry founded the Games in 2014, having been inspired to help wounded and sick military personnel and their families after spending a decade serving with the British Army.

Invictus is one of about 20 charities Harry is heavily involved in, with causes ranging from wildlife to children in need.

During Harry and Meghan's first TV interview after their engagement was announced last November, the couple spoke of their desire to work with various charities, particularly those across the Commonwealth.

"With lots of young people running around the Commonwealth, that's where we are going to spend most of our time hopefully," said Harry, who has been appointed by the Queen to be the Commonwealth's Youth Ambassador.

Mr Fitzwilliams says the aim among royal courtiers is for Harry and Meghan to be a "dynamic duo", working to raise the profile for many charities.

"There's no better place to start than in Australia with Invictus," he said.

Mr Fitzwilliams also believes Harry and Meghan's arrival in Australia will help boost support for the monarchy, particularly in a time of political turmoil that has seen the country change prime ministers seven times in a decade.

"One of the features of monarchy is its continuity and the fact it links with the past," he said.

"It represents consistency and stability, and it's a symbol of national unity. One of the points of monarchy is continuity in tricky times."

Harry and Meghan may have some royal company in Sydney, with hopes Denmark's Crown Prince Frederik will have suitably recovered from his recent back operation to attend the Games, in which Denmark is one of the competing countries. It remains unclear whether Princess Mary will join him.

A visit from football royalty in the form of David Beckham is also on the cards, with the England captain having been made an Invictus ambassador.

He is rumoured to be making his way to Sydney with his designer wife and former Spice Girl Victoria Beckham, both of whom attended Harry and Meghan's wedding at Windsor Castle in May.

As to speculation about where Harry and Meghan might find some quiet time while in Sydney, a luxury harbourside mansion could hold the key.

It's been reported that the royal couple may stay at the multi-million dollar Villa Del Mare in the upmarket suburb of Point Piper.

The Herald Sun in August reported that Harry and Markle would "feel right at home" in the six-bedroom eastern suburbs abode that features several living areas, a bar and an infinity pool.

Australian Associated Press