The Duke and Duchess of Cambridge were among the royals who joined Her Majesty.
Kate, 37, wore a repeat dove grey Alexander McQueen coat with a matching hat - echoing a look she wore during her Australia tour in 2014. Husband William, 36, sported a navy suit with a patterned tie.
They arrived with William’s cousin Zara Tindall, 37, and husband Mike, 40. It’s believed that the Cambridges spent the Easter break with their three children George, Charlotte and Louis at their Norfolk home Anmer Hall.
Photos of the family and the Tindalls at the Burnham Market international horse trials emerged last weekend.
The Duke of Sussex, 34, arrived with his cousin Peter Phillips, 41, and wife Autumn, 40.
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Princess Anne, Prince Andrew, Princess Beatrice and the Earl and Countess of Wessex were also among the royals who greeted the Queen as she arrived.
Her Majesty stood out in a pastel blue ensemble with a fuchsia trimmed hat. The Duke of Edinburgh was not present for the service, as he retired from public duties in summer 2017.
Harry and Meghan were among the social-media savvy royals to wish ‘Granny’ a happy birthday.
The couple took to their new Instagram account to post a carousel of photos, which included images of the Queen as a young woman, with William and Harry when they were children and one with Meghan during their joint visit to Cheshire last year.
The caption read: “Happy Birthday Your Majesty, Ma’am, Granny. Wishing you the most wonderful day! Harry & Meghan.”
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William and Kate also shared a photo of them with Prince George, Princess Charlotte and the Queen from Trooping the Colour 2016 on their @KensingtonRoyal account.
Their message said: “Wishing a very happy 93rd birthday to Her Majesty The Queen!”
The Prince of Wales and Duchess of Cornwall, who were not at the service, also posted a series of photos, new and old, on their Instagram account @ClarenceHouse.