Prince William has paid tribute to his late grandmother the Queen as “one of life's optimists”, as he arrived with wife Kate in the United States ahead of his global environmental project the Earthshot Prize awards.
The Prince and Princess of Wales will spend three days in the city before the ceremony on Friday, handing out five £1million prizes to incredible winners all aiming to solve the world’s biggest environmental problems.
As the royals touched down in Boston on a commercial British Airways flight this afternoon, William said: “Catherine and I are delighted to be back in the United States and are extremely grateful to Governor Baker and The First Lady of Massachusetts for their warm welcome into Boston.
“On this, our first overseas visit since the death of my grandmother, I would like to thank the people of Massachusetts and particularly of Boston for their many tributes paid to the late Queen.
"She remembered her 1976 bicentennial visit with great fondness.


“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.
“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.”

The Prince and Princess of Wales met Boston’s Mayor Michelle Wu at the start of their visit to Boston for the Earthshot Prize awards.
William and Kate were welcomed to City Hall by Ms Wu, the daughter of Taiwanese immigrants and the first Asian American to serve as Boston’s mayor, as their first visit to the US since 2014 risked being overshadowed by a palace race row.
The heir to the throne thanked her and the people of Boston for supporting the awards. “Thank You so much for your help,” he said. “I think people are excited about the awards.”
Kate, 40, was wearing a Burberry dress, a coat by McQueen, and earrings by the sustainable brand Shyla London.
The royal couple also met Ms Wu’s husband Connor Pewarski and their sons Blaise and Cass during a brief audience in the mayor’s office. They appeared to be discussing their own children when the media were briefly allowed into the meeting.
Ms Wu, 37, a Democratic politician and lawyer, is a strong advocate of environmental policies.
She has campaigned for a municipal Green New Deal and signed an ordinance to divest the city council’s investments from companies that derive more than 15 per cent of their revenue from fossil fuels.
She has also announced plans for the city to spend $2 billion on school construction projects as part of the Green New Deal.
More than a dozen Boston landmarks will be lit up green tonight including the City Hall, John F. Kennedy Presidential Library and Museum in tribute to the event.
It is William and Kate’s first official overseas trip since the death of the Queen, with the couple, unfortunately, landing to a shocking racism row involving the heir’s godmother Lady Susan Hussey.
The late Queen's former lady in waiting of more than 60 years was today forced to stand down from her royal role helping the King after making comments to a Buckingham Palace guest about her race and heritage.
The Prince and Princess of Wales are said to be "incredibly excited" about their trip, but have “no plans” to catch up with William’s estranged brother Prince Harry and his wife Meghan Markle who now reside in California, US.

Tonight from Speaker's Corner at Boston City Hall the couple will formally begin the countdown to Earthshot by pressing a giant buzzer to light the city up.
Superstar singer Billie Eilish will lead a stellar line-up for the awards ceremony, founded by William to recognise and scale-up environmental solutions to repair the planet.
Other acts to feature are Annie Lennox, Ellie Goulding and Beyonce proteges Chloe x Halle, performing at the MGM Music Hall in Boston.
A royal source said: "The prize has become the Prince's Superbowl moment of the year, and he looks forward to continuing to use the platform each year to shine a light on some of the most impactful projects doing amazing things around the world to save our planet's future."

The Earthshot Prize is now in its second year, and among the 15 finalists vying for £1 million awarded to each of the five category winners are a cleaner-burning stove initiative in Kenya and a bubble barrier made in the Netherlands to prevent plastics entering oceans.
There are also finalists from the UK for the first time, with two British-based entries being selected.
Notpla Hard Material - a start-up run by Pierre Paslier and Rodrigo Garcia Gonzalez in London - makes packaging from seaweed and plants as an alternative to single use plastic, and has already produced more than one million biodegradable takeaway food boxes for the firm Just Eat.
The other UK finalist - Low Carbon Materials, based in County Durham - uses unrecyclable plastic waste to make traditional concrete blocks carbon-zero.

Broadcaster Sir David Attenborough, a supporter of the Earthshot Prize since its inception, will voice the opening of the show while Oscar winning actress and Earthshot judging panel member Cate Blanchett will narrate a lookback at the 2021 winners.
Actor Rami Malek, who played singer Freddie Mercury in the biopic Bohemian Rhapsody, will present an award as will actress Catherine O'Hara, best known for starring in the film Home Alone, and environmental activist and actress Shailene Woodley.
William and Kate are also keen to meet local communities during their visit to Boston, which is famed for its Irish heritage, sports and history.
During their visit William and Kate will visit the John F Kennedy Presidential Library and Museum with Caroline Kennedy, the late president's daughter.
The prince and princess will learn about the work local organisations are doing to mitigate the risk of rising sea levels to Boston, and when they tour the Greentown Labs, in the nearby town of Somerville, they will get an insight into the development of innovative green technologies.
At the premises of Roca, a non-profit organisation supporting disadvantaged young people, they will hear about the issues they face and Kate, who launched the Royal Foundation Centre for Early Childhood in 2021, will visit the Centre on the Developing Child at Harvard University.