KATE Middleton stunned in a 10-year-old recycled gown as eco-savvy Prince William aptly wore a velvet green suit jacket again at the star-studded Earthshot awards this evening.
The Duke and Duchess of Cambridge shone amongst throngs of famous faces who gathered at Alexandra Palace in north London.
Celebs got creative and dressed to impressed after being asked to "consider the environment when choosing their outfit".
Kate recycled a lilac Alexander McQueen gown with a gold beaded waistband for the inaugural event, that was originally made for her in 2011.
She previously wore the dress that same year for a sparkling BAFTA dinner at the Belasco Theatre in Los Angeles.
Meanwhile, her husband William followed suit, in a dark green velvet blazer he has worn before.
The duke donned the statement piece for the Centrepoint 50th Anniversary Gala at the Roundhouse in London in 2019.
He paired the bold jacket with black trousers and a black turtleneck.
Harry Potter star Emma Watson looked enchanting in a white asymmetric backless tulle dress, made up of 10 dresses from Oxfam.
She clearly got the memo from Dame Emma Thompson, who slammed throwaway culture at the eco-event.
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She said: "If we had shown my parents how people live, how they will wander down the streets and coffee cup, immediately throw it away, eat, throw away, everything throwaway, they would've gone 'what's going on?"
William's Earthshot Prize takes its inspiration from the Apollo moon landings - nicknamed Moonshot - which helped advance mankind's technological achievements.
It features five categories, or Earthshots - Protect and restore nature; Clean our air, Revive our oceans; Build a waste-free world; and Fix our climate - which organisers say if achieved by 2030 would improve life for all.
Every year from 2021 until the end of the decade, winners of the five Earthshots will each receive £1 million to develop their projects.
Earlier this week, Wills blasted billionaires such as Jeff Bezos and Elon Musk for concentrating on "space tourism" instead of the problems on our planet.
He echoed his comments at tonight's ceremony, defiantly declaring: "We don't need a Moonshot, we need Earthshots."
The bash began with a special performance by Coldplay, powered by 60 people peddling bicycles - well in keeping with the green theme.
The Cambridge's called on the world to "unite in repairing our planet", as no A-listers flew in for the event.
The Royals have been passionate when it comes to the environment, with William's father Prince Charles often leading the charge by promoting eco-friendly campaigns.
The Prince of Wales earlier today said he was "very proud" of William's growing commitment to the environment.
In a rare tweet, he urged the world to "come together to inspire, reimagine and build the sustainable future we so desperately need".
Prince Harry, 37, also shared his own plea from across the pond to "stop pillaging" his African "sanctuary" for oil earlier this week.
Earthshot judges include broadcaster Sir David Attenborough, actress Cate Blanchett and singer Shakira.
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Ed Sheeran, Coldplay and KSI performed during the ceremony, and actors Dame Emma Thompson, Emma Watson and David Oyelowo, and Liverpool FC striker Mo Salah, will be handing out the awards.
The ceremony comes ahead of the Cop26 UN climate change conference in Glasgow in a few weeks - which the Queen, the Cambridges, the Prince of Wales and the Duchess of Cornwall will attend.
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