The first three episodes of a docuseries on Prince Harry and his wife Meghan air on Thursday, with expectations of more damaging claims about British royal family life.
The six-part fly-on-the-wall documentary, "Harry and Meghan", promises to lift the lid on events that prompted the pair to quit royal life and move to the United States in 2020.
Trailers aired in the run-up to the much-hyped Netflix release suggest it will further deepen the couple's rift with Harry's family since their acrimonious departure dubbed "Megxit".
One British newspaper said the royal family were viewing the series as a "declaration of war" on the back of the content of promotional clips.
In one, Harry, 38, appears to accuse some within the royal household of leaking and planting stories about the couple in the British press, calling it "a dirty game".
"No one sees what's going on behind closed doors," the prince says. "We know the full truth," he adds in another clip.
"When the stakes are this high, doesn't it make sense to hear our story from us?" Meghan chips in.
The first three episodes of what the US streaming giant vows will be "an unprecedented and in-depth documentary series" will be available from 0800 GMT.
The final three parts are released on December 15.
"It's seriously threatening... the royal family," commentator Richard Fitzwilliams told AFP of the docuseries, branding it "a form of revenge".
"It could be explosive," he said, adding: "It's very difficult to know what the royal family can do about it."
Netflix showcased the first trailer last week, just as Harry's brother William made his first trip to the US as Prince of Wales and heir to the throne, prompting accusations of sabotage.
The timing could barely have been worse for William after Buckingham Palace sacked one of his godmothers as a courtier for using racially charged language to a black British woman at a reception.
For some, the incident reinforced incendiary claims by Meghan, 41, a mixed-race former television actor, that racism within the royal household was one of the reasons for leaving.
The docuseries also appears set to draw parallels between her alleged treatment and that of Harry's mother Princess Diana, who died in a Paris car crash in 1997 while trying to shake off paparazzi photographers.
In the years before her death, Diana had opened up about the torment she felt after marrying into the hidebound British monarchy.
"I was terrified, I didn't want history to repeat itself," Harry says in one trailer, adding: "I had to do everything I could to protect my family."
Meghan notes that she "realized they (Buckingham Palace) are never going to protect you".
The docuseries airs three months exactly since the death of Harry's grandmother Queen Elizabeth II, and a month before the long-awaited publication of his memoirs, "Spare".
As well as the potential for further reputational damage to the monarchy, it is also likely to fuel fresh hostilities with William.
The siblings, who were close after their mother's death, have grown increasingly estranged over recent years.
Although both attended the queen's state funeral in September, relations were noticeably frosty as they failed to even make eye contact.
© Agence France-Presse