Following King Charles' coronation ceremony, the royal family all headed to Buckingham Palace to greet the public from the balcony.
Prince William and Princess Kate, and their three children George, Louis and Charlotte, were all present, alongside Princess Anne, Prince Edward and his family, but Prince Harry was notably absent.
While non-working royals, including Harry and his cousins, Princesses Beatrice and Eugenie, were not expected to be part of the balcony appearance, it is believed that the Duke of Sussex has already departed the UK.
The Daily Mail reported that following the ceremony, Prince Harry's car was spotted leaving the capital and heading in the direction of Heathrow, where he flew into the morning,
While his departure has not been confirmed, during the historic coronation ceremony, Harry was seen confirming his swift exit from the UK.
HELLO! consulted a lipreader who confirmed that Harry told Princess Eugenie's husband Jack Brooksbank: "I will be straight to the airport."
The Duke of Sussex left his wife Meghan Markle at home in Montecito looking after their two children, Prince Archie and Princess Lilibet.
Prince Harry missed the beginning of his son's birthday as he jetted to the UK to attend his dad King Charles' coronation - which was hosted on the same day as Archie's birthday.
Did Prince Harry enjoy the coronation?
While it could have been a worrying experience for Prince Harry, reuniting with his family in such a public setting, it appeared the royal was having a lovely time at the ceremony, chatting animatedly with his cousins, as well as his aunt, Princess Anne.
Princess Anne was spotted jovially greeting her nephew, with Harry responding with a wide, open smile as they chatted.
He also shared a joke with Princess Beatrice's husband Edoardo Mapelli Mozzi, with Edoardo putting a matey arm around Harry in a show of support.
Prince Harry also came face to face with his brother and father - watch the moment the cameras panned to his face as his family members arrived for the coronation, including the Prince and Princess of Wales' children Prince George, Princess Charlotte and Prince Louis.
The Duke, who does not have any formal role in the coronation, looked dapper in a suit for the service instead of a traditional military uniform, though he still wore his military medals.
Before stepping down, Prince Harry wore uniforms to mark his former positions as Captain General of the Royal Marines, Honorary Air Force Commandant of the Royal Air Force Base Honington, and honorary Commodore-in-Chief of the Royal Navy’s Small Ships and Diving Operations.
Because he is no longer a working member of the royal family, he is no longer able to wear his uniform for royal occasions.
We hope the Duke has a safe flight back to the US, and enjoys the remainder of Archie's birthday. Read on for the best photos of Harry from the coronation...