The Queen was joined by her granddaughter Princess Eugenie at a special prize-giving event on Monday night. Her Majesty was presenting a £1million award to Dr Robert Langer for making advances in engineering.
Supported by other senior royals including Princess Anne and Prince Philip, the Queen presided over the ceremony in Buckingham Palace's lavish Throne Room.
The 89-year-old monarch was elegant in a cream and gold dress as she handed the trophy to Dr Langer.
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Dr Robert Langer was awarded The Queen Elizabeth Prize for Engineering
The doctor was given The Queen Elizabeth Prize for Engineering for "his revolutionary advances and leadership in engineering at the interface with chemistry and medicine", according to the award's official website.
It is estimated that over two billion lives have been improved by the technologies that Dr Langer's lab has created.
Following the prizegiving, guests mingled in the Throne Room and Eugenie, 25, was pictured chatting and shaking hands with attendees.
Princess Eugenie supported her grandmother at the prize-giving
The Princess is back on the royal circuit following her move from New York earlier this year. Eugenie, who works at top London art gallery Hauser & Wirth, had lived in the Big Apple since 2013 where she worked at online auction house Paddle8.
Eugenie, however, has made trips back to the US and last month attended a fundraiser with her mother Sarah, Duchess of York and her older sister Princess Beatrice in Manhattan.
The trio were joined by rapper 50 Cent at the BGC Charity Day on Wall Street. The event raised money for the Cantor Fitzgerald Relief Fund which has supported the victims of terrorism, emergencies and natural disasters ever since the September 11 attacks, 14 years ago.