Meghan spent time as an intern at the US embassy in Argentina aged 20 and speaks fluent Spanish, which is likely to help smooth the pair’s encounters with Márquez.
But for long term royal-watchers and historians, the trip rings some alarm bells.
The last members of the Royal family to tour in such high profile under their own steam were the Duke and Duchess of Windsor, whose poor judgement and lack of advice greatly damaged their reputations.
While there is, of course, no risk of the Sussexes getting embroiled in anything equivalent to emerging Nazism, as the Windsors did in 1937, for some, there are some parallels in the approach of the two couples. Prince Harry and Meghan will be travelling with their own small team of staff, but without the British Government advice on in-country protocol and global politics they had to hand in the Royal family. One source, familiar with the work of the Foreign Office, dismissed the trip as “utterly irrelevant” to British interests abroad.
At Kensington Palace, Prince Harry and Prince William both benefited from the advice of Sir David Manning, a former ambassador to the US and Israel. In California, Prince Harry’s new chief of staff, Josh Kettler, is a former executive at Patagonia, the outdoor clothing company, whose LinkedIn profile describes him as “an experienced executive accelerator, organiser, and confidant”.
Anna Pasternak, author of American Duchess: The Real Wallis Simpson, said there was a “real parallel” in terms of non-working royals being invited by foreign governments as “private citizens”, and accepting.
Of the Duke and Duchess of Windsor’s trip in 1937, she said, “They accepted because Edward felt so hurt and angered by the way Wallis had been rejected by the Royal family and he desperately wanted her to experience the pomp and ceremony of a royal tour.
“He wanted Wallis to be addressed as HRH and for people to curtsy to her. I’m not suggesting that Harry wants the pomp and ceremony of a Royal tour, but there is a feeling that he’d like [to elevate] Meghan to the status accorded to her.
“You feel they really value the approval of the people of the country they’re visiting. They can go and be honoured in their own right.”
She added: “When you have this quasi-royal status, you’re seen internationally as a royal and you’re treated as such on tour, but you don’t have the protection of the Foreign Office. This is a high risk tour for them.
“When a country invites you, you’ve got to wonder ‘what’s the agenda?’ In what way does this fit into the narrative, and how they want to be seen on a global scale?”
Michael Cole, the former BBC royal correspondent, said: “There is a danger of their celebrity and willingness to help underprivileged people is being undermined by a certain naivety.”