Prince Harry Blames William for Making Him Wear Infamous Nazi Costume

Prince Harry says his royal sibling, William, and sister-in-law, Kate Middleton, pushed him to dress up in his infamous Nazi uniform to attend a 2005 costume party.

Harry made the STUNNING claim in his hotly anticipated autobiography, "Spare," which is set to be published next week. But, The New York Post reviewed an advanced copy of the book and released an excerpt Wednesday.

In the passage, Harry says he was caught between wearing a pilot uniform and Nazi outfit to the Native and Colonial-themed soiree, so he decided to call William and Kate to get their insights.

"I phoned Willy and Kate, asked what they thought. Nazi uniform they said," Harry reportedly wrote. He said he soon met up with the couple at home and tried on the offensive costume, claiming, "They both howled. Worse than Willy’s leotard outfit! Way more ridiculous! Which, again, was the point."

At the London bash, someone snapped a photo of Harry -- then 20 -- in his Nazi get-up, resulting in a front-page story in The Sun newspaper. The world got to see Harry pictured as a Gestapo soldier with a red armband emblazoned with a Swastika. As a result, there was massive public outrage, creating a huge scandal for the Royal family.

Harry later apologized and referred to the incident as "one of the biggest mistakes in my life."

In another excerpt, published by The Guardian, Harry claims he was physically assaulted by William over Harry's wife, Meghan Markle.

Harry says William called Meghan "difficult," "rude" and "abrasive," triggering a nasty altercation. He says William "grabbed me by the collar, ripping my necklace, and … knocked me to the floor." Harry allegedly suffered a visible back injury.