Prince William and Prince Harry will come together for the unveiling of the statue in honour of their late mother, Princess Diana, on July 1.
Following news that Meghan Markle will stay behind in the US, with Archie and Lilibet Diana, experts say Prince William is also expected to attend the ceremony without his wife, Kate Middleton.
The brothers, who have been at odds, will come face-to-face for the second time in just a few months, following the funeral of their grandfather, Prince Philip.
The two will reunite at the ceremony for Princess Diana, on the grounds of Kensington Palace, where a statue of the late princess will be unveiled.
William and Harry have been working on the project together since 2017. The ceremony and the statue will mark what would have been Princess Diana's 60th birthday.
According to The Daily Telegraph's associate editor Camilla Tominey, the Duchess of Cambridge is likely to stay at home, much like the Duchess of Sussex.
"We've never really been told that family is going to be included in this thing, we know this is the reunion for the brothers on what would have been Diana's 60th birthday on July 1," the royal expert told 9Now's Today in Australia.
"Never any suggestions that the Cambridges would attend along with Prince William and equally, that Meghan and the children would attend with Harry. So I think we may just see them cut solo figures without their families around them," she added.
"All eyes will be on the brothers of course, because everyone's hoping there may be some kind of reconciliation at what is going to be a hugely poignant and significant moment for them, remembering their late mother."
Prince Harry will fly alone from his home in Montecito, US, to England for the event.
He will have to quarantine for 10 days at Frogmore Cottage, much like he did when he attended Prince Philip's funeral.
However, he could leave quarantine earlier than that if he returns a negative Covid-19 test on the fifth day of his isolation.
"Harry has said he will do his utmost to be there," a source close to the Duke of Sussex has previously said.
"He wants to put on a united front with William and pay an appropriate tribute to their mother."
The spot where the statue will be unveiled is said to have been Diana's favourite place in the palace's Sunken Garden.