Prince Harry Will Now Wear Military Uniform for Queen's Vigil on Saturday 'at the King's Request'

For the first time in two and half years, Prince Harry will once again wear a military uniform.

In a change of plans as Queen Elizabeth's funeral processions continue, the Duke of Sussex, who celebrated his 38th birthday on Thursday, will join other members of the royal family who hold military rank in wearing a military uniform at the next ceremonial event for the late monarch on Saturday.

The update comes "at the King's request," according to a palace source, and the decision was made without Prince Harry requesting a change, PEOPLE has learned. The Duke of Sussex was prepared to wear whatever was asked, PEOPLE understands, and his focus is on honoring his grandmother.

Now, Harry will wear traditional regalia for Saturday's solemn vigil at Westminster Hall in London. There, he and his brother Prince William will lead their charge of first cousins, briefly standing at opposite ends of their grandmother's coffin in the medieval hall.

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According to the palace source, William, 40, will stand at the head of Her Majesty's coffin during the 15-minute watch, flanked by his first cousins Zara Tindall and Peter Phillips. Zara and Peter, who do not hold royal titles, are the children of Princess Anne, the Queen's only daughter.

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The Duke of Sussex will stand at the foot of the coffin alongside first cousins Princess Beatrice and Princess Eugenie, the daughters of Prince Andrew, the Queen's second son. Their other cousins, Lady Louise Windsor and Viscount Severn — the children of Prince Edward, the Queen's youngest son — will stand at the middle of the coffin.

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Earlier this week it was announced that Harry — who served two tours of Afghanistan during his 10-year career in the British Army — would not be in uniform during the mourning period as he is no longer a senior working royal. The rule has been temporarily relaxed by his father, King Charles III.

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On Wednesday, Harry and his uncle Prince Andrew both wore morning suits during the ceremonial procession of the late Queen's coffin from Buckingham Palace to Westminster Hall.

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The two men did pin military medals on their suits in recognition of their military service, however, which in Prince Andrew's case included a medal for serving as a helicopter pilot in the Falklands War in 1982. The Duke of York spent 22 years in the Royal Navy.

It was previously confirmed that the Queen's second son would be allowed to wear military uniform to Saturday's vigil as a sign of respect for the late royal, who "peacefully" died at age 96 on September 8.

While Andrew and Harry are no longer senior working royals, a spokesperson for the Duke of Sussex stressed that his focus is on mourning the monarch.

"His decade of military service is not determined by the uniform he wears, and we respectfully ask that focus remain on the life and legacy of Her Majesty Queen Elizabeth II," the spokesperson said.

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Prince Harry last formally wore a military uniform to the Mountbatten Music Festival at Royal Albert Hall in London in March 2020. Then serving as Captain General of the Royal Marines, the prince was dapper in the force's scarlet red dress jacket and full regalia.

Harry, who served in the British Army for 10 years and was deployed to Afghanistan twice, lost his three honorary military titles (Captain General of the Royal Marines, Honorary Air Commandant of RAF Honington and Commodore-in-Chief, Small Ships and Diving, Royal Naval Command) after he and wife Meghan Markle stepped back from their senior royal roles in March 2020.

The prince has since worn dark morning suits to respect mourning dress for the ceremonial events leading up to the state funeral of Queen Elizabeth on Monday.

At this time, he is not expected to wear military attire for the funeral itself.