“They have shown in recent years that they are determined to manage their own PR and news agenda.”

Bond further speculated on the content of the documentary, saying: “It will be interesting to see what this German documentary reveals about their life in California and Meghan’s background. There is a lot we don’t know.

“I don’t necessarily think they have much to hide, but I think their main fear will be that they have no editorial control over this production.”

The news comes following reports that Grunewald, a former collaborator with Germany’s ZDF network on royal features, journeyed to California accompanied by a five-person crew to survey Montecito and collect information from locals.

Anticipated to encompass viewpoints from professionals and journalists, the documentary lists among its contributors ex-Fleet Street Royal journalist Richard Mineards.

In his most recent piece, Mineards wrote: “Los Angeles-based producer Melanie Hillmann grilled me for two hours on my Riven Rock neighbours, Prince Harry and Meghan Markle, under director Ulrike Grunewald.”

“The interview is airing in due course as part of a prime-time documentary on ZDF Royal.”

Grunewald.’s productions include numerous royal documentaries such as ‘The Windsors’ in 2009, ‘The Queen’ in 2015, and a television series called ‘How German is the Queen?’

By 2020, her portfolio included ‘Man Fergie! The Duchess and the Secret of the Windsors,’ and in 2021, she contributed to the creation of the documentaries ‘Princess Diana’s Dangerous Legacy’ and ‘The Queen and the Power of Images.’/

The Duchess and the Secret of the Windsors,’ and in 2021, she contributed to the creation of the documentaries ‘Princess Diana’s Dangerous Legacy’ and ‘The Queen and the Power of Images. ‘.