The event celebrated and awarded funding to environmental projects that will better the world for future generations, and among the people who handed out awards were David Beckham, Home Alone star Catherine O'Hara and No Time to Die star Rami Malek, while Billie Eilish performed remotely for audiences.
WATCH: Prince William and Kate arrive at Earthshot Awards - and Kate looks sensational
Following the success of the ceremony, guests mingled with the royal couple with former footballer David breaking protocol and leaning in to give Princess Kate a kiss on the cheek.
Other pictures saw William and Kate enjoying a laugh with singer Chloe and Halle Bailey, and their good friend Ellie Goulding, who sang at their wedding in 2011.
TRENDING: Prince William and Princess Kate front star-studded Earthshot Awards event – best photos
William opened the ceremony by telling the audience: "When I founded this Prize in 2020, it was with the ambition to harness the same spirit of ingenuity, that inspired President John F. Kennedy to challenge the American people to put a person on the moon within a decade. So, it has been an honour to share the stories of our Earthshot winners and finalists from the heart of his hometown."
"I believe that the Earthshot solutions you have seen this evening prove we can overcome our planet's greatest challenges, and by supporting and scaling them we can change our future,'' he continued. "Alongside tonight’s winners and finalists, and those to be discovered over the years to come, it’s my hope the Earthshot legacy will continue to grow, helping our communities and our planet to thrive."
David leans in to give Kate a kiss on the cheek
"And in the same way the space effort six decades ago created jobs, boosted economies, and provided hope, so too can the solutions borne of tonight’s Earthshot Prize winners," William continued.
"The decisions we make now will affect generations to come which is why we must choose the path of hope, optimism, and urgency to repair our planet."
The royal pair with Chloe and Halle
Kate and William looked fabulous at the extravagant event with the Prince of Wales in a dapper black tie suit, while the Princess of Wales looked stylish in a bright-green dress, paying homage to the green event.
The five 2022 Earthshot Prize winners were Mukuru Clean Stoves, Kheyti, Indigenous Women of the Great Barrier Reef, Notpla, and 44.01.
Kate looked gorgeous
The Clean Our Air award was presented by Kate to Kenyan organisation Mukuru Clean Stoves, a start-up providing cleaner-burning stoves to women in Kenya to reduce unhealthy indoor pollution and provide a safer way to cook.
Taking to the stage, Kate said: "To breathe clean air is something so many of us take for granted. But sadly for millions of people around the world, it is not a given. From smog enveloping cities to the impact seen in nature, air pollution poses a threat that knows no borders. heartbreakingly over 250 million children under the age of five are breathing polluted air every single day.
"And this fact is even harder to hear because we know the significant impact pollution has on our lifelong development. But there are reasons to be hopeful. And I'm delighted to see the work of our three finalists and their solutions to clean our air."
Kate and William arrive at the ceremony
Actress Catherine gave the Protect and Restore Nature award to Kheyti, a pioneering solution for Indian smallholder farmers to reduce costs, increase yields and protect livelihoods in a country on the frontlines of climate change.
Revive our Oceans award was given by Shailene Woodley to Australia's Indigenous Women of the Great Barrier Reef, an inspiring women-led program that combines 60,000 years of indigenous knowledge with digital technologies to protect land and sea.
Rami and Kate enjoy a laugh
David Beckham presented the Build a Waste-free World award to Notpla, a British-based startup which is creating an alternative to plastic packaging from seaweed and has already made more than 1 million takeaway food boxes.
Oscar winner Rami Malek also took to the stage to give Oman-based organisation 44.01 the Fix our Climate award. 44.01 was created by childhood friends who have developed an innovative technique to turn CO2 into rock, and permanently store it underground.
David left William shocked
The Prince and Princess of Wales were greeted with a standing ovation as they took to stage for the start of the ceremony, which referenced the colonists who came to Boston 400 years ago.
Elizabeth Solomon, a member of the Massachusetts tribe at Ponkapoag, asked attendees to "respect the lands and waters".
Speaking about the crisis, Rami said during the green carpet: "This is the greatest crisis that we are facing in our lifetime and it will probably be the greatest crisis that future generations are facing as well. But hopefully we can lessen that challenge for them by the actions we take right now."
Catherine O'Hara was also in attendance
Attendees were treated to various musical performances, including Annie Lennox, who performed Here Comes the Rain Again and Billie Eilish who made a virtual appearance to sing My Future.
Chloe x Halle gave a soaring rendition of Nina Simone's classic Feeling Good.
Annie Lennox performed during the ceremony
The Earthshot initiative was inspired by John F. Kennedy's Moonshot ambition, and his daughter, Caroline, was present at the event, hosted in Boston.
William spent time with Caroline ahead of the event, as she took him on a guided tour around the John F. Kennedy Presential Library and Museum.
The awards ceremony is being taped on Friday, and will be broadcast on Sunday.
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