Surprise! Kate Middleton makes appearance with royal family at RAF celebration

It was previously thought that the Duchess of Cambridge would not attend

The Duchess of Cambridge delighted fans as she joined the royal family at Westminster Abbey on Tuesday morning. Kate, who is on maternity leave until the autumn, was not confirmed to attend the service, but the mother-of-three made a surprise appearance with her husband Prince William. Led by the Queen, the royals were attending a service to mark the centenary of the Royal Air Force.

Prince Charles and the Duchess of Cornwall, Prince Harry and Meghan Markle, Prince Edward and the Countess of Wessex were among the royal party, as were Princess Anne and Vice Admiral Sir Tim Laurence, Prince and Princess Michael of Kent and the Duke and Duchess of Gloucester. The royals were greeted at the abbey doors by the Dean and Chapter of Westminster, before taking their seats.

Watch the royals arrive at the service:

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After the service, the monarch, accompanied by Prince Charles, will present a new Queen's Colour to the RAF on the forecourt of Buckingham Palace and make a short speech. She will then head to the palace balcony to watch a flypast and Feu de Joie. It has not been confirmed who will join Her Majesty on the iconic viewpoint, but royal watchers are hoping Kate will make a second appearance.

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Kate made a surprise appearance as patron of the RAF Air Cadets

The royals have already had a busy start to the week, with Prince Louis' christening taking place on Monday afternoon. The 11-week-old Prince was christened at the Chapel Royal of St James's Palace in London, with Prince William, Kate, Prince George and Princess Charlotte making their official debut as a family of five. The Cambridges were joined by Harry, Meghan, Charles and Camilla.

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Kate, 36, looked absolutely thrilled at the christening and sweetly bounced her baby boy as she arrived at the chapel. She was heard describing her sleeping son as "very relaxed and peaceful". The Duchess added with a smile: "I hope he stays like this."