The Prince and Princess of Wales are said to be "super excited" to begin their trip to Boston later today, ahead of the second annual Earthshot Prize ceremony on Friday.
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A Kensington Palace spokesman said: "This is a huge moment for the Prince and Princess. It's their first visit to the US since 2014. And they're both super excited to be here.
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"It's also a huge moment for the Prince of Wales as he hosts his second Earthshot ceremony on Friday night and we are delighted that we were able to do that in Boston.
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"The Prince and Princess were really struck by the warm response of the American people to the news of their trip this week. And they are really looking forward to meeting communities across Boston over the next few days and trying to meet as many folks as possible."
© Photo: Getty ImagesThe royal couple jetted off to Boston on Wednesday
The spokesman said the city had been "the natural choice" for the event as the Prize was inspired by Boston-native President John F Kennedy's famous 1962 moonshot speech, which committed to putting a man on the moon within a decade.
Prince William's Earthshot Prize aims to find and scale up solutions to some of the world's biggest environmental challenges and each year will award five prizes of £1million to scalable ideas and projects that can help to repair the planet.
The Prince and Princess are flying commercial and will travel in a hybrid Range Rover during the visit.
© Photo: Getty ImagesSongstress Billie Eilish is due to perform on Friday
Stars including Billie Eilish, Annie Lennox, Ellie Goulding, Chloe x Halle, Rami Malek, Catherine O'Hara and Shailene Woodley will perform at the glittering awards ceremony on Friday and William and Kate will both appear on stage.
Earthshot Prize CEO Hannah Jones said: "The Earthshot Prize will indeed on Friday feel like our pinnacle, Superbowl, World Cup moment. The city is buzzing."
William and Kate will begin their visit at a special event with the Mayor of Boston Michelle Wu and JFK's daughter, Ambassador Caroline Kennedy.
© Photo: Getty ImagesPrince William launched the Earthshot Prize in 2020
On Thursday 1 December they will hear how local organisations are combating the risk of rising sea levels in Boston and will tour Greentown Labs to learn about green technologies in development.
William and Kate will also hear how disadvantaged young people are being supported by the non-profit organisation Roca.
The spokesman said: "The Prince and Princess were really keen to also see some of the best practice things that are being done in Boston around the areas of work that they do in the United Kingdom."
© Photo: Getty ImagesThe royal delivered a poignant speech last year
Ahead of the Earthshot ceremony, the Prince will visit the John F Kennedy Presidential Library and Museum and the Princess will visit the Centre on the Developing Child at Harvard University.
The Earthshot Prize ceremony will air on BBC One at 5.30pm on Sunday December 4, and will be streaming on PBS in the United States from Monday December 5, on Multichoice across the African continent and on YouTube.
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