From the vantage point of the Duke of Wellington's old office, which overlooks Horse Guards Parade, Camilla, Harry, Meghan and Kate and the other members of the Royal Family watched the finale of the event.
Watched by large crowds, the newlyweds arrived in a horse-drawn carriage as part of a procession.
He rode out alongside Prince Charles, Colonel of the Welsh Guards, the Duke of Cambridge, who is Colonel of the Irish Guards and Princess Anne, who is Colonel of the Blues and Royals.
Meghan Markle and Prince Harry are back from their honeymoon - and back on royal duty.
Meghan wore an off-the-shoulder Carolina Herrera dress - shoulders are one body part royals usually cover up, especially during the day - for her debut at the annual Trooping the Colour ceremony.
Bringing Prince Harry's new bride along with her is a "is a really positive sign of favour, encouragement and endorsement by the Queen", Robert Lacey, historical consultant for Netflix's "The Crown", tells People.
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Prince George and Princess Charlotte were among the ranks, but Prince Louis was a no-show and is unlikely to be seen before his christening, tipped to be next month. She is due to join Queen Elizabeth in Cheshire for her first solo appearance alongside the Queen on Thursday.
Riding in the ceremony for the first time is the Duke of York in his new role as Colonel of the Grenadier Guards. Meghan has become particularly close to her father-in-law, who walked her down the aisle and was instrumental in helping Meghan and Harry with wedding planning.
Scroll through for all the fantastic photos of the British royal family at Trooping the Colour 2018 on June 9. Kate, who is married to Harry's older brother Prince William, wore a dress by Alexander McQueen and a hat by Juliette Botterill.
Queen Elizabeth II also selected a blue ensemble, choosing a dress and hat in a bolder blue than the shade chosen by Middleton and Parker-Bowles.
"I'm quite proud and I know that a lot of other people are proud of me as well", he was qouted as saying by the BBC.