The Duke and Duchess of Cambridge joined schoolchildren at Kew Gardens alongside some famous faces, ahead of the inaugural Earthshot Prize Awards ceremony on Sunday.
Prince William and Kate also met the Mayor of London, Sadiq Khan, naturalist and presenter Steve Backshall MBE, and Olympian Helen Glover to take part in a series of activities alongside the students from The Heathlands School, Hounslow, as part of the Generation Earthshot initiative.
Recent findings from The Children's Commissioner's Big Ask show that young people are concerned about the future of the planet, with 39 percent of children asked in the UK identifying the environment as one of their main worries about the future.
Generation Earthshot informs that interest and encourages students and their teachers around the world to generate ideas to solve the world's greatest environmental challenges. It aims to unlock the potential of the next generation of inventors, innovators and leaders who will inherit our world and inspire in them the enthusiasm to develop new solutions and protect our planet.
READ: Kate Middleton to be joined by Ant and Dec at royal outing
WATCH: Prince William and Kate Middleton join Steve Backshall and Helen Glover at Kew Gardens
William said: "Education is such an important part of protecting our planet. We must inspire in the next generation the optimism, confidence and enthusiasm to chase those solutions and to continue building a more sustainable future.
"We know that young children already identify the climate as one of their biggest worries, and Generation Earthshot aims to educate and encourage them that together we can find the answers.
"Children can be uniquely creative and I can't wait to see some of the ideas that are shared with us."
The Duke and Duchess will attend the star-studded Earthshot Prize Awards at London's Alexandra Palace on Sunday 17 October, where the first five winners will be announced.
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William and Kate joined different tables as they took part in a series of fun and thought-provoking activities with the students.
And we'd love to know what the tickled the Duchess so much!
Prince William was engaged in learning alongside the children.
The environment is a cause close to the Duchess' heart, as well as her husband's.
Students wrote their environmental hopes and ideas on notes for other participants to read.
Kate was fascinated by the students' work.
The royals posed for a photo with the students who attended the special day.
The royal couple clearly enjoyed their day.
The Cambridges posed for a group photo with Steve Backshall, Helen Glover and Mayor of London, Sadiq Khan.
The Mayor of London said: "It's been great to work with the bright young leaders of our future today to develop ideas on how to address the climate and environmental crisis.
"I want London to be a zero-pollution city so that no child has to grow up in our city breathing toxic air and I'm determined that we continue to tackle the twin dangers of air pollution and the climate emergency so that we can deliver a future that’s greener, fairer and more prosperous for everyone."
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