For the highly-anticipated occasion, Princess Kate floored crowds in the most decadent outfit, serving up Hollywood glamour for the glittering event. But in a pleasant surprise to fans, Princess Kate's gown was rented, with HELLO! confirming that the royal's dress is from the British rental platform HURR, and was designed by Solace London.
WATCH: Princess Kate stuns in bold green dress as she and Prince William front Earthshot Awards
The Sabina Maxi Dress is a floor length modern gown featuring an exaggerated neckline, and retails for $525. The mother-of-three quite literally elevated her showstopping outfit by slipping into a pair of white sparkling stiletto heels by Gianvito Rossi.
She accessorized with an emerald green choker that was once owned by William's late mother, Diana the Princess of Wales.
Kate wore her brunette locks loose and styled in gorgeous waves, and her make-up was kept naturally beautiful with a brown smokey eye and a neutral pink lip color.
Prince William looked suave beside his beloved wife, wearing a black tuxedo with black bowtie.
Kate looked glam in the rented look
GET THE LOOK
Cassie bias green dress, £135, Revolve
Green satin dress, £139, Mint Velvet
Green dress, £151, Karen Millen
Dubbed Prince William's "Superbowl moment," the glitzy ceremony drew an A-list crowd at the MGM Music Hall at Fenway in Boston.
Among those presenting awards were Oscar-winning actor Rami Malek, Home Alone and Schitt's Creek star Catherine O'Hara and environmental activist and Big Little Lies star Shailene Woodley.
GET THE LOOK
Green choker, £18.15, Etsy
"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," said Kate during a speech while naming the Clean Our Air winner.
"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."
Earthshot Prize council members Sir David Attenborough and Cate Blanchett both provided voiceovers during the ceremony, which was presented by UK broadcaster Clara Amfo and US actor Daniel Dae Kim.
The ambitious, decade-long, global Prize programme aims to discover and scale up solutions to the planet's biggest environmental challenges.
Among the ideas competing this year are a cleaner-burning stove initiative in Kenya and a bubble barrier made in the Netherlands to prevent plastics entering oceans.
William described the finalists as "innovators, leaders, and visionaries" and said they proved there are "many reasons to be optimistic about the future of our planet".
He went on to say: "They are directing their time, energy, and talent towards bold solutions with the power to not only solve our planet's greatest environmental challenges, but to create healthier, more prosperous, and more sustainable communities for generations to come".
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