King Charles III will ride on horseback in London alongside his son William, the Prince of Wales, in his first birthday parade on June 17.
Buckingham Palace has announced that the Queen Consort, Camilla, and Princess of Wales, Catherine, will watch from carriages in the traditional show of splendour which will involve the Trooping of the Colour.
The official birthday celebrations will come only weeks after the coronation on May 6 while King Charles celebrates his actual birthday, a lesser affair, in November. He will turn 75 at the next occasion.
Charles III officially became King upon the death of his mother Queen Elizabeth II in September and has been completing his duty in the months since. However, with the funeral arrangements and public mourning of the Queen largely overshadowing his ascension to the throne, 2023 is likely to be the year he makes a greater personal impression as monarch.
As part of the announcement on Thursday, Buckingham Palace also unveiled new honorary royal colonel roles within armed forces regiments with special ceremonial roles.
Princess Catherine has been named Colonel of the Irish Guards, taking over the role from her husband Prince William - who was promoted to his father’s former role upon the death of the Queen. William also takes Colonel of the Welsh Guards from Charles.
Queen Consort Camilla will become colonel of the Grenadier Guards, a role she takes from Prince Andrew - who has been in the shade after the public fallout around allegations of sexual assault, which he has denied.
The King and Prince of Wales will ride horses as part of the procession where more than 1,400 soldiers will parade, with 200 horses and hundreds of army musicians taking part.
The procession will be held around Horse Guards Parade, before the royal contingent watch a Royal Air Force fly past from the balcony of Buckingham Palace - with crowds expected to gather in The Mall.