The Duke and Duchess of Sussex have been accused of firing another volley in the war of the Windsors with their headline-grabbing Netflix trailer.

“I don’t see how anyone could view it as anything other than a declaration of war,” one insider said of Friday’s bombshell trailer.

It dropped just as Prince Harry’s brother and sister-in-law, the Prince and Princess of Wales, got their milestone trip to the US underway.

Its timing – in time for US breakfast TV – also appears to dash any hopes the strained relationship between Harry and heir-to-the-throne Prince William might be on the mend.

William and Kate will be the guests of honour at a glittering awards ceremony in Boston for his $9 million Earthshot Prize later on Friday. William is also tipped to meet US President Joe Biden.

But it was the 60-second promotion for Harry and wife Meghan Markle’s upcoming “at-home” Netflix series that stole the show on Friday.

“If tomorrow is Prince William’s Super Bowl, then here is your half-time show,” royal correspondent Omid Scobie – who penned the biography Finding Freedom about the Sussexes and is widely considered to be part of their inner-circle – tweeted as the promo dropped.

Tweet from @scobie

The promo reveals intimate and previously unseen photos of Harry and Meghan in public and private settings.

“No one sees what’s happening behind closed doors,” Prince Harry says in the trailer. “I had to do everything I could to protect my family.”

The Duchess of Sussex is seen wiping away tears and sitting with her hands covering her face while on her phone. She closes the trailer with: “When the stakes are this high, doesn’t it make sense to hear our story from us.”

The show debuts on December 8.

A distressed Meghan Markle in a clip from the new promo. Photo: Netflix

Royal sources said William and Kate had not seen the trailer – which also features an image of them with stony faces at a Commonwealth ceremony at Westminster Abbey with Harry and a pregnant Meghan in 2019.

“They have deliberately ­gate-­crashed the Boston trip and taken advantage of an external ­situation for their own agenda. There’s no other way to put it,” one insider told Britain’s Mirror newspaper.

“Harry is well aware how important it is not to overshadow the work of other members of the family. Yet this is exactly the type of playground tactics being employed here.”

Majesty magazine editor-in-chief Ingrid Seward questioned the timing of the promo’s release.

“Putting the trailer out while William and Kate are in Boston looks like an ambush by Harry and Meghan. They are quite good at that kind of thing and timing is everything,” she told London’s Sun newspaper.

“But looking at how well the Prince and Princess of Wales have been received in Boston by the crowds and the great community work they are doing, I don’t think the attempted ambush has worked.”

Kate and William ignored the family drama on the first day of their US trip.

They took in an NBA game (reportedly receiving a few boos and chants of “USA” from the crowd) and visited environmental projects. Crowds lined the streets to see them and there was also a sweet moment with a small boy dressed as a royal guardsman, who presented the princess with a bunch of flowers.

“They were all smiles — but you could see Kate also had a real steely look,” one onlooker told The Sun.

Tweet from @RoyalFamilyITNP

Kate and William’s trip is also threatened to be overshadowed by another royal racism row.

On Wednesday, a member of the British royal family’s household left her role after making “unacceptable and deeply regrettable” comments about race and nationality to a woman at a grand reception at Buckingham Palace, a spokesperson said.

Ngozi Fulani, who was born in Britain and works for a domestic abuse support group, wrote on Twitter that the royal aide had repeatedly asked her: “What part of Africa are you from?” when she attended an event hosted by Camilla, the Queen Consort, this week.

British media identified the royal aide as Lady Susan Hussey, the 83-year-old godmother of Prince William.

The incident follows accusations of royal racism from Harry and Meghan in their 2021 Oprah Winfrey interview.

Meghan told Winfrey that one unnamed member of the family had asked, before their son Archie was born, how dark his skin might be.

The allegation clearly stung the monarchy, which promised any such issues would be treated very seriously, and Prince William to remark days later: “We’re very much not a racist family.”

-with AAP