In the memoir, he also makes a series of accusations and revelations about his brother and sister-in-law, Prince William and Kate, the current Prince and Princess of Wales, exposing how their relationship deteriorated.
Spare is being published near the third anniversary of Prince Harry and Meghan announcing their planned retreat from royal life — January 8, 2020 — but also coincides with the Princess of Wales's birthday on January 9.
Prince Harry wrote about how he had left his wifealone at Diana’s grave during a visit to her family’s Althorp estate.
“When I returned, she was on her knees with her eyes closed and her palms flat against the stone,” Prince Harry wrote.
He added that she told him she had asked Diana for “clarity and guidance”.
Prince Harry said in Spare that he and the Duchess of Sussex had rowed out to his mother’s final resting place on an island on the Althorp estate in 2017.
Spare is dedicated to Diana — who died in a car crash in Paris when Prince Harry was 12 — his wife and children Archie and Lili.
In clips of an interview promoting his book with Good Morning America, Prince Harry said Diana would have been “sad” about her sons’ fractured relationship.
“I have felt the presence of my mum more so in the last two years than I have in the last 30,” he said.
In Spare, Prince Harry refers to his mother as “mummy” and said his father, now King Charles III, did not hug him when he sat on his bed and told him Diana had died.
The book also includes several stories involving the current Princess of Wales and clashes between the brothers.
Prince Harry claimed that it was the Prince and Princess of Wales who encouraged him to wear a Nazi uniform to a fancy dress party in 2005.
“I phoned Willy and Kate, asked what they thought. Nazi uniform, they said,” he wrote. “They both howled. Worse than Willy's leotard outfit! Way more ridiculous! Which, again, was the point.”
Meghan also upset Kate by saying she must have “baby brain” during a phone call in the run-up to the royal wedding in 2018.
During a reconciliatory tea, Prince William, then the Duke of Cambridge, “pointed a finger” at the Duchess of Sussex, saying: “Well, it's rude, Meghan. These things are not done here,” to which she said: “If you don't mind, keep your finger out of my face.”
After that, there was a clash over lip gloss.
Prince Harry recalls an “awkward moment” when his wife asked Kate to borrow some lip gloss before their Royal Foundation Forum appearance in 2018.
“Kate, taken aback, went into her handbag and reluctantly pulled out a small tube,” Prince Harry writes. “Meg squeezed some on to her finger and applied it to her lips. Kate grimaced.”
The duke wrote that the four “should've been able to laugh” about the moment but the press “sensed” it was “something bigger” and so Kate was “on edge” that she was now “going to be compared to, and forced to compete with, Meg”.
The prince has admitted that he and Meghan were offended when the Prince and Princess of Wales switched place cards and changed seats at their wedding.
He added that Kate also made Meghan cry over a bridesmaids' dress fitting for Princess Charlotte.
Prince Harry wrote that the Princess of Wales had texted his wife the week of the wedding about a “problem” with Princess Charlotte's dress.
Kate said the princess's dress was “too big, long and baggy” and that the child “burst into tears when she tried it on”.
He wrote that the dresses, made by Givenchy, had been hand-sewed based solely on measurements so it made sense that they would need some tweaks.
But Kate reportedly said that the dress needed to be remade from scratch.
Prince Harry wrote that he later found Meghan in tears “on the floor” over the disagreement but the next day Kate apologised, bringing over flowers and a card.
Kensington Palace and Buckingham Palace have declined to comment.