After joining the Queen for the first time at Chelsea yesterday, the Duke and Duchess of Cambridge were back on royal duty this afternoon at the last of her annual Buckingham Palace Garden Parties.William and Kate made a long-awaited appearance with the 90-year-old monarch and Princesses Eugenie and Beatrice on the palace terrace at 4pm as the National Anthem was played, before making their way into the crowds to chat with members of the public and sip tea.
The Duchess had thriftily recycled an Alexander McQueen coat, worn on another important occasion - Prince George's christening in 2013.
She accessorised with a Jane Taylor hat, while the Queen was striking in a bold azure coat by Stewart Parvin. Her blue hat was with a carnation spray was by Rachel Trevor-Morgan hat.
Her sister Beatrice opted for something a little more high fashion, wearing a £1,695.00 floral silk dress by Burberry Prorsum. She accessorised with a black cocktail hat with a white rose by London milliner Nerida Fraiman.
As she mingled with guests the Duchess paused for a chat with her PA Natasha Archer and hairdresser Amanda Cook Tucker - who also cut Prince William's hair in his youth.
The Queen's cousin, the Duke of Kent, was looking smart in a top hat as he mingled with guests at the event.
It was a family affair with another first cousin, Prince Richard, Duke of Gloucester, attending alongside his wife Birgitte the Duchess of Gloucester.
It was, remarkably, the first time the Duke of Cambridge had attended a Garden Party – an annual royal rite of passage – despite being second in line to the throne.
The Duke and Duchess of Cambridge also invited the 'unsung heroes' of the medical team that helped deliver their two children to a Buckingham Palace garden party today.