The duchess, who stunned in an off the shoulder dark navy dress, bespoke fascinator and nude heels, held on tight to Harry, who was wearing his No1 RAF uniform. According to the site, she also wore matching Manolo Blahnik suede pumps and a hat from Stephen Jones Millinery.
While many expected Prince Charles to walk his mother to his seat, the 92-year-old made her way down the aisle on her own, just behind Charles and Camilla.
The Duchess of Sussex opted for a new silhouette. One day you're shaking hands with the Archbishop of Canterbury at Prince Louis's christening, the next you're staring up at the sky for another jet fly-past over Buckingham Palace. They will attend a commemorative service, followed by a flypast including up to 100 aircraft.
Inside the Abbey, Prince Harry was spotted cracking a joke with Prince Andrew as the Duchess of Sussex beamed at her husband as she attempted to contain her laughter.
While this is a meaningful day for Will and Kate's third child, July 9 already marks a memorable date for the Royal clan: It was on this day in 1947 that Queen Elizabeth and Prince Philip announced their engagement, and posed for photos at Buckingham Palace.
While The Duke of Cambridge became a fourth generation RAF member, with active duty as a search and rescue helicopter pilot.
Meghan Markle, whose Duchess style profile has shifted dramatically from the early pale pinks and off-whites she wore during the first few weeks, arrived at the Abbey in a black A-line Dior gown cut at her knees and featuring the same neckline as her now iconic Givenchy wedding dress: the bateau.