The couple were seen talking to Jason Knauf, chief executive of their Royal Foundation, on the green carpet.
Royal fans took to Twitter to beam over Kate and Prince William’s outfit choices for the award ceremony.
Cherylsmilesx wrote: “Beautiful couple.”
MsPaigeJoslin tweeted: “I’m obsessed with Prince William’s green velvet jacket with the black turtle neck!! Catherine looks absolutely stunning, as always!”
Sapphireblues3 said: “So proud of them! Just stunning, Our future King and Queen consort.”
Organizers of the Earthshot awards asked guests to “consider the environment when choosing their outfit” for the awards ceremony.
No guests flew into London to attend the ceremony.
Emma Watson took to the green carpet in an upscaled wedding dress made from 10 dresses from Oxfam.
Clara Amfo, co-presenter of the awards spoke about Prince William’s acting skills.
Ms Amfo said: “He has been really great company and I am sure you saw our advert and he was quite the actor.
“We took a few takes and he took considerably less.”
Prince William’s velvet blazer was also hailed by royals fans on social media.
Farchie03 wrote: “Breathtakingly beautiful.
“Easy in green, Prince William!”
LisaTant tweeted: “One of the only times I have seen Prince William out-style Kate. Love the velvet blazer!”
Source: EXPRESS CO UK