Meghan Markle and Prince Harry
Meghan Markle warned about upcoming Australia trip with Prince Harry. Pictured: Markle and Prince Harry wave as they leave Windsor Castle after their wedding to attend an evening reception at Frogmore House, hosted by the Prince of Wales on May 19, 2018 in Windsor, England. Getty Images/Steve Parsons

Meghan Markle was warned about her upcoming trip to Australia by one expert.

The Duke and Duchess of Sussex are set to fly to Sydney in October for the Invictus Games. However, according to Queen Elizabeth II's former spokesman, the upcoming trip will be a real test for the new royal.

"She's good at talking to people but it will be a real baptism of fire," Dickie Arbiter said (via Express). "They will have a very demanding schedule. The Duchess will have to get used to local customs with the eyes of the world on her."

Although some things might be new to Markle, Arbiter is confident that she can make it considering her progress as a royal. He is positive that the duchess has already learned most of the things that she needs to know.

"The Duchess of Sussex being from the US the concept of monarchy is a bit alien," Arbiter continued. "It’s been a great learning curve she has taken in her stride and managed incredibly well. She and Harry have shown they are getting on incredibly well and always look so fantastically in love. With experience will come confidence and in the next few months I have no doubt we will see her come out of her shell even more."

Arbiter also noted Markle's relationship with the Queen. According to him, the pair has a "tremendous rapport." He pointed out at the photos of the former "Suits" actress and the monarch laughing together and explained that Her Majesty "is very relaxed in her company and she will become relaxed in the Queen's company."

For Prince Harry and Markle's trip to Australia, they will reportedly be staying at a multi-million dollar waterfront home. Harper's Bazaar reported that the Duke and Duchess of Sussex chose Villa del Mare as their home while in the Land Down Under. The luxury mansion has six bedrooms, a private butler's residence, wine cellar, gym and infinity pool.

In related news, Prince Harry and Markle were last seen together in Balmoral. The couple traveled to Scotland to join the Queen for the summer and enjoyed long walks and barbecues during their visit.