•Prince William and Catherine have arrived in the US, where they will hand out awards for their Earthshot Prize.
•The Earthshot Prize was launched in 2020 to search for innovative solutions to problems facing the planet.
Image: REUTERS
US President Joe Biden plans to meet the Prince and Princess of Wales on Friday in Boston, the White House has said.
Prince William and Catherine have arrived in the US, where they will hand out awards for their Earthshot Prize.
Shortly after landing, the prince thanked the US city for hosting his environmental awards.
The Earthshot Prize was launched in 2020 to search for innovative solutions to problems facing the planet.
The arrival of the royal couple came as a spokesperson for Prince William sought to distance the royal from a race row back in the UK.
His godmother Lady Susan Hussey, a member of the Royal Household, resigned after repeatedly asking a black British charity boss where she was "really" from.
The Prince and Princess of Wales launched the countdown to Friday's event by lighting up the city's landmarks green.
Crowds stood in the rain to welcome them to the city hall in Boston, home town of former US president John F Kennedy - the Earthshot prize is based on his 'Moonshot' challenge to put a human on the moon.
"Like President Kennedy, Catherine and I firmly believe that we all have it in ourselves to achieve great things, and that human beings have the ability to lead, innovate and problem-solve," Prince William told the crowd.
He said he wanted to thank the people of Boston for "their many tributes paid to the Queen", on this, his first overseas visit since her death.
"My grandmother was one of life's optimists. And so am I. That is why last year we launched the Earthshot Prize with the ambition to create a truly global platform to inspire hope and urgent optimism as we look to save the future of our planet," he said.
"To the people of Boston, thank you. I'm so grateful to you for allowing us to host the second year of the Earthshot Prize in your great city.
"Catherine and I can't wait to meet many of you in the days ahead."
Later on Wednesday evening, the royal couple attended an NBA basketball game between the Boston Celtics and Miami Heat at TD Garden, sitting courtside with Celtics owner Wyc Grousbeck and his wife Emilia Fazzalari.
A planned trip for the royal couple to New York earlier this year was cancelled following the death of the Queen. The couple was last in the US in 2014 in a trip that included a reception at the White House with the then president Barack Obama and his then vice-president Joe Biden.
When asked about the arrival of the royal couple in Boston, the White House said that President Biden intends to greet them and his team are "working through the details".
It is far from the ideal start to this visit.
Events at Buckingham Palace on Monday have been embarrassing and distracting.
The focus for the Prince and Princess of Wales in the United States was due to be environmental innovation, optimism about the future and meetings with a wide range of communities in Boston.
Before the royal couple had even arrived in the city, their spokesperson had issued a strongly worded statement condemning racism and supporting the decision of Prince William's godmother, Lady Susan Hussey, to step aside.
Timing mattered here. Condemnation of her remarks from both Buckingham Palace and Kensington Palace was swift and unequivocal.
In issuing a statement at the very start of their American visit, the Prince and Princess of Wales have made their position and feelings on the matter explicitly clear - there is no place for this kind of comment and questioning within the royal household.
And all this just a few days before the Duke and Duchess of Sussex are due in New York to receive a human rights award from the Robert F Kennedy Foundation. Robert Kennedy's daughter, Kerry, says Harry and Meghan were chosen for the honour due to their "heroic stand" against "structural racism" within the royal family.
Five winners of the Earthshot Prize will be announced in Boston on Friday - each will be given £1m ($1.2m) to develop their environmental projects.
Among the 15 finalists are the inventors of a bubble pump designed to catch plastics before they reach the ocean.
For the first time there are also finalists from the UK, including London start-up Notpla, which makes packaging from seaweed and plants as an alternative to single-use plastic.
Prince William has described the people in the shortlist for the prize - now in its second year - as "innovators, leaders and visionaries".
The prize was inspired by US President Kennedy's "Moonshot" programme, which resulted in the US Apollo lunar launches and the first man setting foot on the Moon in 1969.