The Prince of Wales is scheduled to attend the United Nations climate conference in Brazil in the coming weeks, as announced by the royal household.
Prince William and King Charles appeared together on Thursday night at a gathering ahead of the environmental conference, which is set to be held in the northern Brazilian city of Belém.
Father and son were participating in the Natural History Museum reception, marking an rare public appearance together at a pre-COP30 gathering co-hosted by the British authorities.
The King has been a longstanding advocate of biodiversity preservation - and Prince William has inherited the mission, with his own climate innovation awards, which will be hosted in Rio preceding the UN meeting.
Palace insiders have described William's involvement at the upcoming climate summit as assuming an important role in "environmental negotiations".
The monarch and his heir, making a joint entrance in the official car, were welcomed participants featuring environmentalists, researchers, climate change campaigners, foreign representatives and politicians.
This participation involved presentations in concert with President Emmanuel Macron of France and other world leaders at the Marine Economy Conference in the Principality of Monaco earlier this year.
The COP30 summit will align with the William's personal Earthshot environmental awards, which will wrap up in Rio de Janeiro the previous day he participates in the COP summit on 6 November.
Recently the prince referred to the Earthshot finalists as "contemporary champions".
King Charles has been a influential participant at earlier environmental conferences, giving the opening address in the United Arab Emirates for COP28, including the statement: "We are custodians of the planet, not its owners".
"I have spent a large proportion of my life trying to raise awareness about the survival risks facing us over global warming, global temperature increases and species extinction," the monarch informed participants.
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