The Prince Of Wales and Duke of Sussex have joined forces to remember their late friend Henry van Straubenzee.

In a now rare show of unity from the brothers, a joint letter written for a carol concert for the ‘Henry van Straubenzee Memorial Fund’ at St Luke’s Church in Chelsea, London, on December 1, featured both siblings’ signatures.

The Daily Mail reported it is understood to be the first time in at least a year they have together put out a statement.

Their jointly-signed letter in memory of ‘Henners’ was carried in the order of service at Thursday’s carol service attended by close friends including the Princess Of Wales’ sister and brother, Pippa and James, and their spouses.

It said: “As you gather together under this roof tonight, the charity is supporting 51 nursery, primary and secondary schools in rural Uganda, where 1,700 projects have been completed and over 35,000 children, each year, are benefitting by receiving education they wouldn't have otherwise.

“Where there were old, dilapidated and unsafe school buildings, there are now schools which have their own water supplies, proper safe buildings to learn in, and essential hygienic facilities which are conducive to a healthy learning environment.”

Henry was killed in a car crash as a passenger on December 14, 2002, aged 18, and the charity in his name set up by his parents Alex and Claire supports schools and helps construct, restore and improve buildings.

But Prince William and Harry’s message said about the foundation ending: “It is with a mixture of great pride and sadness therefore, that tonight we share with you Claire and Alex’s plan to embark on a gradual winding down of the charity.

“Henry's legacy will live on through the incredible achievements of his mum and dad have accomplished over the years. For those of us who knew Henners, we will always miss his mischievous charm and hilarious sense of humour.

“But everyone here tonight, his family and many friends, are able to come together and remember him twenty years after his death by being here at St Luke's Church to celebrate his life and legacy at this Christmas time.”

As patrons of the charity, William and Harry have attended the annual carol service in his memory along with their wives in previous years.

Henry’s brothers Thomas and Charlie remain close to the two brothers and are godparents to William’s daughter Princess Charlotte and Harry’s son Archie.

The letter added: “Claire and Alex tell us that their work is not over yet! As long as funds permit, they will continue to monitor their schools, ensuring that the children of South East Uganda receive that vital education, providing the opportunity to escape poverty as they grow up, and hopefully that of their own children in the future.

“Thank you for all your continued support in making this possible, and for the everlasting support of the van family who we all love and adore. Have another enjoyable evening and a very Happy Christmas.”