Yui Mok/Getty Prince William
Prince William will not be traveling to New York City this month as planned.
The Prince of Wales, 40, will no longer be attending the Earthshot Prize Innovation Summit on September 21 following the death of his grandmother, Queen Elizabeth. The gathering falls during the time of mourning that's continuing for seven days past the monarch's funeral on September 19.
On September 8, Buckingham Palace announced the long-reigning monarch died "peacefully" died at age 96 at her beloved Balmoral Castle.
The summit will still go on, co-hosted by other Earthshot Prize organizers and Bloomberg Philanthropies. There, the groups will bring together inaugural finalists and last year's Earthshot Prize winners. Attendees will also include Matt Damon, Bill Gates, Cate Blanchett and even Oscar the Grouch.
William was set to address the guests alongside former New York City mayor Michael R. Bloomberg, who works to help scale and replicate the Earthshot solutions as Global Advisor to the winners of the Earthshot Prize. The royal heir's attendance at the September summit was first announced in August.
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Plans are still likely in motion to host the Earthshot Prize ceremony in Boston in December. Earlier this summer, Prince William revealed the historic Massachusetts capital would be the site of the second annual global environmental awards. He and wife Kate Middleton were expected to attend.
Sharing the exciting news in an August Twitter video, the future King said, "In 2022, we're back and bringing Earthshot to the USA where we'll award the next five winners of the Prize."
The clip then cut to Red Sox All-Star Xander Bogaerts from the home of the iconic baseball team at Fenway Park.
"And we will be doing it right here in Boston," Bogaerts said from the outfield.
Inspired by President John F. Kennedy's famed 10-year goal of landing on the moon (known as Moonshot), the Earthshot Prize aims to promote impactful approaches to the world's most pressing environmental challenges. Prince William launched the environmental initiative in 2020.
The @EarthshotPrize is back and this year, we're heading to Boston!
Five more winners. Game-changing solutions. More potential to save our planet. Boston, we'll see you in December #EarthshotBoston2022 pic.twitter.com/gE24ioqNFh
— The Prince and Princess of Wales (@KensingtonRoyal) July 20, 2022
Fittingly, the announcement that the second awards ceremony will be held in Boston came on the anniversary of the moon landing. The John F. Kennedy Library Foundation serves as host partner, alongside Mayor Michelle Wu and the City of Boston.
During their trip to Boston, Prince William and Kate were also set to spotlight the "inspiring" city for its work on addressing the impacts of climate change and building a resilient future, the senior royals said in a statement.
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The Prince and Princess of Wales were last in the U.S. nearly a decade ago, visiting New York in 2014.
The couple's first joint visit to America came shortly after their royal wedding in 2011 when they headed to Los Angeles.
The Earthshot Prize recently became an independent charity apart from the couple's Royal Foundation, with William taking on the role of president.
"The urgency of the situation can't be overstated," the prince exclusively told PEOPLE following the inaugural Earthshot Prize ceremony in London in October 2021. "But through the Earthshot Prize, I want to show people across the world why there is reason to be hopeful."