Kate Middleton makes surprise appearance at RAF celebration along with cheeky George and Charlotte

One day after her son Prince Louis’ christening, Kate Middleton made a surprise appearance alongside her royal relatives. The Duchess of Cambridge joined her husband Prince William, as well as Prince Harry and Meghan Markle at Westminster Abbey to mark the centenary of the Royal Air Force on Tuesday, July 10. The mom-of-three, who is on maternity leave through autumn, looked characteristically elegant wearing her go-to designer Alexander McQueen

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><img alt=VIEW GALLERY Kate joined William, Meghan and Harry at the RAF service on July 10 Photo: Getty Images

The Duchess’ pale blue bespoke coat dress that featured winged lapels and a tailored bodice is nearly identical to the primrose yellow one she wore to Harry and Meghan’s royal wedding in May and the ivory one from Princess Charlotte’s christening in 2015. Kate completed her look on Tuesday with a Sean Barrett hat, Her Majesty’s teardrop earrings, Gianvito Rossi pumps and her Air Cadets Dacre Brooch, which is considered the highest award any female Air Cadet can achieve.

><img alt=VIEW GALLERY Members of the British royal family gathered on the palace balcony for a flypast display Photo: Getty Images

Queen Elizabeth, the Duchess of Cornwall and the Duchess of Wessex were all seen sporting brooches. The newly-minted Duchess of Sussex, who donned Dior for the occasion, was the only royal who did not wear one to the 100th anniversary celebrations. After the RAF service, the royals returned to Buckingham Palace for the “Presentation of the Colors” on the forecourt and later gathered on the palace's balcony to view a flypast display.

GALLERY: MEGHAN AND KATE'S BEST PHOTOS TOGETHER

><img alt=VIEW GALLERY George and Charlotte took in the excitement from a palace window Photo: WENN

Although they were not on the balcony with their parents and Gan-Gan, Prince George and Princess Charlotte were spotted catching a glimpse of the excitement from one of the palace’s windows with their Spanish nanny Maria Teresa Turrion Borrallo. Cheeky Charlotte, three, stuck out her tongue, while George, four, watched in awe. The young royals joined their parents and baby brother at Prince Louis’ christening the day prior. While her older children appear to have outgoing personalities behind closed doors, Kate revealed that her youngest child is "very relaxed and peaceful.”

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