Stunning behind-the-scenes images have been released showing the Prince and Princess of Wales at rehearsals for the Earthshot Prize, the environmental awards taking place in the United States.
William's environmental awards will see singer Billie Eilish lead a stellar entertainment line-up during a ceremony - dubbed the prince's "world cup" moment - that aims to celebrate and scale up environmental solutions to repair the planet.
Ahead of the event being staged on Friday evening at the MGM Music Hall at Fenway, the prince is due to meet US President Joe Biden.
In a black-and-white image released of Kate she is seen in silhouette walking across the stage of the theatre as an image of a cloud-filled sky is projected behind the royal.
In another image William is photographed laughing as he chats to someone off camera with broadcast equipment in the background of the picture.
Prince William wore a pair of trousers that he’d had for 20 years after he asked guests at his inaugural Earthshot Prize awards to "consider the environment when choosing their outfit" for the bash.
The Duchess of Cambridge arrived wearing a lilac Alexander McQueen dress made for her in 2011, which she previously wore to a BAFTA dinner in Los Angeles.
Among the celebrities at the ceremony were Harry Potter star Emma Watson, who walked the "green carpet" at London's Alexandra Palace wearing a wedding dress made of 10 dresses from Oxfam, Dame Emma Thompson and Sir David Attenborough.
No stars had flown to London and guests were asked by organisers to "consider the environment when choosing their outfit".
William launched his prize to find solutions to the planet's environmental problems and overcome the pessimism felt by many on its future.
Judges include broadcaster Sir David Attenborough, actress Cate Blanchett and singer Shakira.
The couple's three-day trip to Boston, which ends on Friday, has been somewhat overshadowed by the race row that saw William's godmother Lady Susan Hussey resign as a royal aide.
Lady Hussey repeatedly questioned a prominent black British-born domestic abuse charity boss about where she "really came from".
Ngozi Fulani, who was born in the UK and runs a black women's domestic abuse charity, said the royal aide asked her: "Where do you come from?"
In a conversation that followed, Hussey continued to ask "what nationality are you?", "where do your people come from?" and "what part of Africa are you from?"
Buckingham Palace released a statement condemning the "unacceptable and deeply regrettable comments" and confirmed she had "stepped aside from her honorary role with immediate effect."
Ngozi told the Mirror: "[What she did] was racism. Through and through. It was prolonged racism.
"The fact that it was just done in the open in front of people, on a day when we should be working towards violence against women."
A trailer promoting the Duke and Duchess of Sussex's Netflix docuseries was released on Thursday, with the timing interpreted by some royal commentators as a snub to William and Kate.
The series is set to be split into six episodes and according to Netflix "explores the clandestine days of their early courtship and the challenges that led to them feeling forced to step back from their full-time roles in the institution".
And the streaming service adds that it will also feature "friends and family, most of whom have never spoken publicly before about what they witnessed".
