Since their feud became public, royal events that have been attended by both Prince William and Prince Harry have been rare.
However, last June, the warring brothers managed to put their differences aside to honour their late grandmother the Queen during her Platinum Jubilee celebrations - in what was Harry and wife Meghan's first public appearance at a royal event since quitting the monarchy.
Despite coming together at the event, the pair were seated far apart and were not seen chatting or even standing next to each other - but it still made for a tense service, which was also attended by William's wife Kate.
After the service, the couple were seen chatting on the steps of the cathedral as they waited for their car to take them to the Guildhall for a lunch reception.
And a lipreader has revealed what he believes they said during their exchange, which included a clear instruction for Kate from William.
According to lip reading expert John Cassidy, as they emerged on to the steps, Kate remarked on the service saying: "It went very well, very well" with William replying: "Yes, perfect."
Afterwards, William could be seen waving to the crowd saying hello, and Mr Cassidy says the prince then turned to Kate and said: "Wait for that to move, then we can go."
Meanwhile, a body language expert who looked at the couples at the same event believes William gave Harry the "opposite of an acknowledgement" and a "barrier gesture".
Body language expert Judi James told the Mirror that William adopted a "barrier gesture" as he and wife Kate walked past the pew where his brother sat on the way to his seat.
Judi explained: "Harry looked firmly resigned to the back row here and was not sitting behind his brother as he was for the last service of remembrance.
"Harry’s expression did suggest some relief as he joked with Zara as he searched for his car on the way out and he threw a wide, open-mouthed grin in her direction from the pews, but otherwise he fell into a haunted eye expression with some rapid blinking to suggest inner anxiety, leaning in and down to Meghan when she spoke as though keen to get some support.
"There was the opposite to an acknowledgement from William as he walked past Harry’s row during the parade out of the service.
"Sucking in his lips and with his chin pulled up in a gesture of resolve he appeared to turn his head in the other direction for a moment, raising his order of service high in a barrier gesture."
After the Jubilee last summer, William and Harry were forced together just months later after the death of their late grandmother the Queen.
They even joined together with their wives Kate and Meghan to carry out a joint walkabout in Windsor to look at floral tributes and greet thousands of wellwishers.
But despite the seeming temporary truce, it appears their bond has further deteriorated after Harry and Meghan's Netflix series and Harry's controversial memoir Spare.
