January 5, 2023 | 7:28pm

Prince Harry got into a “duel” with Prince William and King Charles III astir his determination to quit the royal household after Prince Phillip’s ceremonial successful April 2021.

In this jaw-dropping memoir, “Spare,” Harry reflected connected the “secret meeting” astatine Frogmore Gardens betwixt the 3 men arsenic they tried to mend their breached relationship.

However, what was meant to beryllium a productive speech rapidly turned sour arsenic the 2 brothers started getting “heated,” prompting their begetter to intervene.

According to the Duke of Sussex, the King begged his sons not to “make [his] last years a misery” arsenic they went backmost and distant with tempers flaring.

At 1 point, the Prince of Wales adjacent swore connected their precocious mother’s life that helium genuinely wanted his younger member to beryllium blessed — which didn’t beryllium close with Harry.

The remark caught him disconnected defender arsenic the brothers lone uttered those 3 words successful “times of utmost crisis.”

In fact, Harry “didn’t believe” oregon “fully trust” that William was being honest, saying “even those ineffable words couldn’t acceptable america free.”

Prince William, Prince Harry and King Charles successful  suits. Things got “heated” betwixt the siblings earlier Charles stepped in. WireImage

Harry walked distant from the gathering convinced that if his household didn’t cognize wherefore helium near beingness arsenic a royal successful the archetypal place, past possibly they “never” knew him astatine all.

The ex royal didn’t shy distant from exposing intimate details of the siblings; analyzable narration — from referring to William arsenic his “archnemesis” to exposing an alleged carnal altercation betwixt them implicit Harry’s wife, Meghan Markle.

an older photograph  of King Charles holding a babe  Prince Harry alongside Prince William. Harry shared shocking details astir his narration with his older member successful his caller memoir. Tim Graham Photo Library via Get

Harry claimed that a “piping hot” William, 40, “attacked” him successful 2019 astatine Kensington Palace aft calling Markle “difficult,” “rude” and “abrasive.”

“It each happened truthful fast. So precise fast. He grabbed maine by the collar, ripping my necklace, and helium knocked maine to the floor,” Harry recalled successful the memoir, which volition his US shelves connected Jan. 10.

Prince William, Prince Harry and King Charles laughing.The brothers allegedly got into a carnal altercation successful 2019. Getty Images

Although William apologized astatine the time, helium is reportedly furious with his younger brother for airing retired their soiled laundry.

Palace insiders told Vanity Fair connected Thursday that determination is “a monolithic spot issue” betwixt the member arsenic William fears Harry volition merchandise each of their conversations to the press.

Prince William, Prince Harry and King Charles and Camilla Parker Bowles successful  black. The Prince of Wales is reportedly furious that Harry is spilling their secrets. Samir Hussein/WireImage

“For now, helium isn’t going to beryllium commenting oregon reacting,” different root told the outlet anterior to the book’s release. “His program is to thrust this each out. At the extremity of the day, helium volition inactive beryllium the Prince of Wales, and that’s what helium is focused on.”

Reps for Buckingham Palace dittoed this sentiment, telling Page Six that the royal household would not beryllium commenting connected immoderate of the allegations made successful “Spare.”