The Queen’s grandchildren stood guard around her coffin in London on Saturday, hours after their parents held an emotional vigil in the Palace of Westminster.
Notably, the Duke of Sussex joined his brother the Prince of Wales in wearing uniform around the coffin in Westminster Hall, ahead of the Queen’s state funeral on Monday.
Harry, who saw action on the front line during two tours of duty in Afghanistan, has previously been denied the chance to wear his military uniform as he publicly mourns, because he is no longer a working royal.
Watch ITV News' continuous live coverage of mourners queuing to pay their respects to the Queen Lying in State in Westminster Hall
But royal sources say the King has decided his youngest son can wear uniform for the vigil, saying he will stand at the foot of the coffin, with William at the head.
Despite being a former Army officer, he has been in civilian dress for official events, including walking behind his grandmother’s coffin on Wednesday when it was carried to Westminster Hall for lying in state.
Prince William was flanked by his cousins Zara Tindall and Peter Philips, the children of the Princess Royal; while Prince. Harry stood alongside the Duke of York’s daughters Princesses Beatrice and Eugenie.
The Earl of Wessex’s children Lady Louise and Viscount Severn stood near the middle.
Members of the public were surprised to see the Queen's grandchildren holding a vigil having heard that it would be later in the evening.
One mourner said: "It struck you quite hard how historic the moment was that you were participating in."
Another said: "We didn't know they were in there. We walked in and we thought, that's Prince Harry, goodness."
On Friday evening, the Queen’s children – King Charles III, the Duke of York, the Princess Royal and the Earl of Wessex – took part in their own vigil.
The King, Anne, Andrew and Edward had solemn looks on their faces as they stood vigil around their mother’s coffin, with their heads bowed throughout as members of the public filed slowly past them.
It comes as final preparations are under way for the funeral on Monday, with politicians and royal dignitaries from around the world expected to arrive throughout the weekend.
King Charles met chiefs of staff at Buckingham Palace on Saturday and visited police headquarters to thank the emergency services for their work in planning the funeral.
The King also met with five prime ministers in the afternoon - Canadian PM Justin Trudeau, Australia leader Anthony Albanese, The Bahamas’ PM Philip Davis, the PM of Jamaica Andrew Holness, and Jacinda Ardern, PM of New Zealand.
World leaders have been making their way to London to sign the book of condolence at Lancaster House and to attend the Queen's funeral on Monday.
Canadian PM Mr Trudeau tweeted his tribute: “Her Majesty Queen Elizabeth II served for her entire life, and bore the weight of her duties with impeccable grace.
“Sophie and I are in London for Her Majesty’s funeral – and today, we marked the solemn occasion by signing the book of condolences.”
Australian leader Mr Albanese tweeted: “It was an honour to meet with His Majesty King Charles III at Buckingham Palace.
“I extended my personal condolences and those of the Australian people to the King.”
Meanwhile, US president Joe Biden touched down at Stansted Airport on Saturday evening.
On Sunday, Ms Truss will meet Irish Taoiseach Micheal Martin, Canadian premier Justin Trudeau, Polish President Andrzej Duda and US President Joe Biden at Downing Street.
She will have an audience with the King before attending his reception for visiting heads of state at Buckingham Palace on Sunday.
Charles concluded his tour of the home nations on Friday, starting his day with a visit to Wales, after trips to Northern Ireland and Scotland in recent days.
Meanwhile, thousands of people continue to queue to see the Queen’s coffin laying in state, with the wait down to around 12 hours by Saturday evening.
Two thousand people will gather inside Westminster Abbey in London on Monday for the Queen’s funeral.
Some 800 people, including members of the Queen’s Household and Windsor estate staff, will attend the committal service afterwards at 4pm in St George’s Chapel, Windsor Castle.
After the funeral, the King and members of the royal family will walk behind the Queen’s coffin to Wellington Arch when it leaves Westminster Abbey, before it is driven to Windsor on the state hearse.
The remarkable life of the Queen remembered in our latest episode of What You Need To Know