The Duchess of Cambridge was forced to step in after Princes William and Harry both "refused to put to bed" their "hurtful rift", a source has claimed.
Kate knew the brothers, who have always been extremely close, needed to make up after a "complete and utter break-down in communication".
The mum-of-three is clearly very fond of her brother-in-law, and they struck up a strong bond after she joined the Royal Family in 2011.
So she offered him a key piece of advice in a bid to get things back to normal, and he took it.
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She told Harry to offer William and "olive branch", which led to him and Meghan Markle inviting the Cambridges over to their new home Frogmore Cottage after the Royal Family's Easter Sunday church service.
They had tea and chatted for around 30 minutes at Frogmore Cottage .
A palace source said: “The Duchess and Harry have developed a very close bond over the years.
“Kate is acutely aware of the importance of William and Harry getting along, not just because of perception but their collective responsibility to the monarchy as a whole.
Feuding Prince William and Harry had 'disastrous row that couldn't be defused'
“Harry has acted as counsel to his brother throughout William and Kate’s more turbulent years, and the three of them had gone on to form the most tremendous partnership.”
Insiders said the brothers had a “disastrous row that could not be defused” over the different paths in life they are now on.
Meghan Markle and Prince Harry share cute photo as they prepare to welcome royal baby
While William is being prepared to become King one day, Harry is forging his own path which “before meeting his wife Meghan had been severely lacking”, another source said.
Royal watchers noticed the brothers appeared to avoid each other at the Easter Sunday service, and stood either side of Zara and Mike Tindall before greeting the Queen at St George’s Chapel.
Meghan and Harry are due to welcome their first child any day now, and royal fans are on the lookout for any sign the newest royal has arrived.
