boston - Britain's Prince William capped a three-day visit to Boston by meeting with U.S. President Joe Biden on Friday, ahead of announcing his Earthshot Prize environmental award winners at a gala event.

The Prince of Wales shook hands with Biden and spoke quietly in the winter cold near the water outside of the John F. Kennedy Memorial Library and Museum. He also met Caroline Kennedy, the late president's daughter, and told her that the stories of the Earthshot Prize winners were an inspiration.

William once again paid homage to President Kennedy, 'the man who inspired our mission,' and said the 'game-changing' solutions were being offered to protect the planet.

Kennedy's legacy loomed large during the visit by William and his wife, Kate. William named his environmental award the Earthshot Prize, drawing inspiration from Kennedy's moonshot speech that mobilized the nation in 1962 by declaring astronauts would set foot on the moon before decade's end.

William became heir apparent less than three months ago with his grandmother's death, but he was already crowned Britain's chief environmentalist.

During his visit to Boston, William drew praise for his drawing attention to pollution and climate change and the need to scale up solutions to address them. Those efforts were culminating Friday evening, when the five winners of the royal couple's Earthshot Prize for environmental innovators were to be announced.

'I just appreciate that they are using platform and publicity to bring attention to meaningful climate work,' said Joe Christo, who is managing director of Stone Living Lab, which researches nature-based approaches to climate adaptation, and was among those who met the royal couple at Boston Harbor on Thursday.

'I do know his dad is a big environmentalist,' he said. 'He seems to be doing a great job continuing that legacy.'

Britain's Prince William, Prince of Wales, and Catherine, Princess of Wales, attend the second annual Earthshot Prize Awards ceremony at the MGM Music Hall at Fenway, in Boston, Dec. 2, 2022.

The Earthshot Prize offers 1 million pounds ($1.2 million) in prize money to each of the winners of five separate categories: nature protection, clean air, ocean revival, waste elimination, and climate change. The winners and all 15 finalists also receive help in expanding their projects to meet global demand.

The winners were to be announced at Boston's MGM Music Hall as part of a glitzy show headlined by Billie Eilish, Annie Lennox, Ellie Goulding, and Chloe x Halle. The show will also feature videos narrated by naturalist David Attenborough and actor Cate Blanchett.

William is following in the footsteps of his environmentally minded grandfather Prince Philip - the late husband of Queen Elizabeth II - and more recently his father and Elizabeth's successor, King Charles III.

In his capacity as prince, Charles was for decades one of Britain's most prominent environmental voices, blasting the ills of pollution. Last year, he stood before world leaders at a U.N. climate conference in Scotland and suggested the threats posed by climate change and biodiversity loss were no different than those posed by the coronavirus pandemic.

But now that he is king, Charles is expected to be more careful with his words and must stay out of politics and government policy, in accordance with the traditions of Britain's constitutional monarchy. This year, he did not attend the U.N. climate conference in Egypt.

The caution presents an opportunity for William to step into that role as the royal family's environmental advocate and speak more forcefully about the issues once associated with his father.

There is no better example than the Earthshot Prize.

'It's a huge deal to Prince William,' Joe Little, the managing editor of Majesty Magazine. 'He knows he can attract attention from the most important people. That really is the core of the Boston trip.'

After attending a welcome event Wednesday at City Hall and then a Boston Celtics game, the royal couple spent much of Thursday hearing about the threats of climate change and solutions in the works.

They got a firsthand look at some innovations at a green technology startup incubator called Greentown Labs, in Somerville. Among them were solar-powered autonomous boats and low-carbon cement.

'Climate change is a global problem, so it's so important to have global leaders talking about the importance of taking action,' said Lara Cottingham, vice president of strategy policy and climate impact for Greentown Labs.

William and Kate also chatted with Katherine Dafforn, co-founder of Living Seawalls, an Australian company that designs environmentally friendly ocean infrastructure. 'For all of us, time is ticking,' William said.

The couple's first trip to the U.S. since 2014 is part of the royal family's efforts to change its international image. After Elizabeth's death, Charles has made clear that his will be a slimmed-down monarchy, with less pomp and ceremony than its predecessors. William and Kate arrived in Boston on a commercial British Airways flight.