'You knew that was coming!': Hilarious moment King Charles comes to the rescue when Archbishop of Canterbury Justin Welby forgets his lines in Coronation rehearsal

Practicing for what would be the biggest moment in his time as a member of the clergy, Justin Welby can be forgiven for a case of nerves. And new footage of rehearsals for King Charles III's coronation, released by the BBC ahead of being broadcast in full on Boxing Day, reveals that not even the Archbishop of Canterbury is immune to fluffing his lines. Charles III looks amused as the Archbishop of Canterbury, Justin Welby, fluffs his lines during the rehearsal for his Coronation as seen in the documentary Charles III: The Coronation Year King Charles III is crowned with St Edward's Crown by the Archbishop of Canterbury on May 6 - with no lines forgotten this time Queen Camilla is crowned by Archbishop of Canterbury Justin Welby during her coronation ceremony in Westminster Abbey The Archbishop later joked that his memory was 'about as good as our spaniel's — in other words, zero' King Charles III and Prince William at the Coronation rehearsal in Westminster Abbey The off-the-cuff remark prompts laughter from everyone present - including the King. King Charles III stands after being crowned during his coronation ceremony in Westminster Abbey on May 6 King Charles III, Queen Camilla, Prince George of Cambridge, Archbishop of Canterbury Justin Welby, Annabel Elliot, Lieutenant Colonel Major Jonathan Johnny Thompson at the coronation ceremony King Charles III pictured in full regalia in the Throne Room at Buckingham Palace The footage shows the Queen gingerly walking towards the exit, accompanied by her three-grandsons and great-nephew. King Charles III and Queen Camilla in the Gold State Coach return back to Buckingham Palace from Westminster Abbey after the coronation service King Charles III and Queen Camilla travelling in the Gold State Coach built in 1760 and used at every Coronation since that of William IV in 1831 King Charles III and Queen Camilla on the balcony of Buckingham Palace wave crowds after the coronation ceremony Prince Edward, Duke of Edinburgh, Lady Louise Windsor, James, Earl of Wessex, Sophie, Duchess of Edinburgh, Princess Charlotte of Wales, Catherine, Princess of Wales, Prince Louis of Wales, Prince William, Prince of Wales on the Buckingham Palace balcony Members of the royal family appear on the Buckingham Palace balcony during the Coronation of King Charles III and Queen Camilla She recalls: 'I thought back to being two years old and watching the Queen's Coronation on a tiny black and white television – and there goes this golden coach with my sister in it.