One royal source told The Mirror the siblings have talked ahead of today’s event.

The source said: “They [William and Harry] have been in contact but, to put it mildly, the situation remains incredibly strained.

“The ceremony should be and will ultimately signify a coming together for the right reasons.

“This commemoration has been a long term project for both William and Harry and both of them are adult enough to put any feelings to one side to ensure the day goes off without a hitch.

“Certain things don’t need to be said, it’s an unspoken agreement to do what is right in that moment, just as they have said before, this is about their mother’s life and celebrating her legacy.”

Relations between the siblings have been strained since Harry made the decision to step back as a senior member of the royal family.

The anticipated statue unveiling on Thursday will be the first time the brothers have been face-to-face since Prince Philip’s funeral in April.

Royal experts have said the project is incredibly personal to both brothers and have speculated the event may offer a chance to heal the rift.

READ MORE: William and Harry could make ‘finest tribute’ to Princess Diana

“I think it’s more likely to be the beginning of a slow reconciliation. But it’s hopeful.”

Prince Harry arrived back in the UK alone on Friday and has been quarantining at Frogmore Cottage.

On Wednesday, the Duke of Sussex made his first public appearance since touching down where he made a surprise appearance at a children’s charity event in London.