Prince William outlines 'hopes' for Keir Starmer in hushed one-to-one conversation

Upon the pair's meeting, William told Sir Keir: "Hopefully you enjoy it" as the pair had a quiet discussion for several minutes before entering the main hall.

The duo are in Brazil for the awards ceremony of the Earthshot Prize, a global environment award founded by the Prince which provides a £1million grant to five winners each year for "innovative solutions to environmental challenges".

William launched the prize to channel "positive action" around the environment and spoke about the next generation of environmentalists during an event ahead of the ceremony.

He said: "I think the Earthshot rise is a classic example of change. Rather than talk about it, we're doing it, and that's where I want to be."

Speaking at the event, attended by some of the finalists, he added: "These people in here are the true action heroes of our time and change will come by backing them, not by what I do.

"And so I want to surround myself with people who want to make change and do good in the world."

Many other celebrities and world leaders are also in the city for the ceremony, including Leonardo DiCaprio, Energy Secretary Ed Miliband, Former PM of New Zealand Dame Jacinda Ardern, Mayor of London Sadiq Khan and former F1 World Champion Sebastien Vettel.

Pop princess Kylie Minogue and Canadian star Shawn Mendes, both of whom will perform at the event, were also seen with Prince William on the "green carpet".

Posing for photos alongside the prince, Mr Mendes thanked him for the kindness he showed to his mother, saying: "She's still shaking, thank you."

In response, William explained he heard it was her birthday and had organised for a cake with candles to mark her big day.

Prior to the ceremony, Sir Keir met four Brazilian children representing representing "mini-Cop" who had been working on environmental projects.

Speaking to students aged 11 to 18 on the sidelines of the ceremony, the PM said the opinions of younger generations needed to be key in decisions made about the climate.

He told them: "You have to live with them longer than anyone else, so we need your voice."

Sir Keir also met with Adam Root, the chief executive of Matter, a firm which makes sustainable filters to capture microplastics from washing machines.

Praising the project, the Prime Minister said it would be "really good to do more" when Mr Root said: "We'd love to talk to you about it."

Awards at the Earthshot ceremony are presented in five categories: protect and restore nature; clean our air; revive our oceans; build a waste-free world; and fix our climate.

The Prince's project has already had ceremonies hosted in London, Singapore, Cape Town and Boston since its beginning in 2020.