PRINCESS Kate was said to have found a walkabout with Meghan Markle and Prince Harry one of the "hardest things she's ever done", the Sun reported.
In the days after the Queen's death the "fab four" appeared to put their differences aside as they stepped out of a car at Windsor Castle and spoke to mourners.
Kate, Prince William, Harry and Meghan walked side by side as they made their way toward the crying crowds, in what seemed to be a show of unity.
However, a veteran royal correspondent has now claimed that was far from the truth.
In his new book, Robert Jobson says a source close to the Royal Family revealed it was in fact an "illusion".
The correspondent writes in his book Our King, which has been serialised in the Mail this weekend: "Catherine later admitted to a senior royal that, such was the ill feeling between the two couples, the joint walkabout was one of the hardest things she'd ever had to do."
Jobson's claims come after Harry suggested in his memoir Spare that the relationship he and Meghan had with William and Kate was fragile.
In one shocking segment of his autobiography he revisited the infamous pre-wedding row between Meghan and Kate.
The duke insists that his sister-in-law the Princess of Wales was responsible for the argument.
Recounting the incident, Harry said Kate sent Meghan a text which read: “Charlotte’s dress is too big, too long, too baggy.
"She cried when she tried it on at home.”
He explains that Kate was apparently unwilling to meet Meghan’s tailor at Kensington Palace and the two women exchanged abrupt text messages about the issue just four days before the wedding.
Harry wrote: “Meg asked if Kate was aware of what was going on right now. With her father.
"Kate said she was well aware, but the dresses. And the wedding is in four days!” “Yes, Kate, I know . . .”, his fiancée replied sharply.
Harry said: “Meg didn’t reply to Kate straight away. Yes, she had endless wedding-related texts, but mostly she was dealing with the chaos surrounding her father.
“So the next morning she texted Kate that our tailor was standing by.”
He added: “A short time later I arrived home and found Meg on the floor. Sobbing.
“I was horrified to see her so upset, but I didn’t think it a catastrophe. Emotions were running high, of course, after the stress of the last week, the last month, the last day.
“It was intolerable but temporary. Kate hadn’t meant any harm, I told her.”
The next day Kate arrived with a bouquet of flowers and apologised to Meghan, Harry claims.
In another excerpt Harry claimed his brother and Kate encouraged him to wear his notorious Nazi uniform to a fancy dress party.
Harry says William and Kate “howled with laughter” when they saw him dressed up in the offensive outfit for the party in 2005.
The Sun broke the shocking story with a front-page photo of the royal dressed as a Nazi soldier complete with a red armband emblazoned with a swastika, when the prince was 20 years old.
The Prince later apologised for his actions.
In another bombshell claim, Harry said he pulled out a thong made of ermine for Kate during his speech at her wedding to Prince William.
Harry – who claimed he was not his older brother’s best man – said an American man wrote to him about wanting to make something special for Catherine.
Kensington Palace declined to comment on Jobson's claims.