The Prince and Princess of Wales have been pictured behind the scenes during rehearsals for the Earthshot Prize being staged in the US city of Boston.

William’s environmental awards will see singer Billie Eilish lead a stellar entertainment line-up during a ceremony – dubbed the prince’s “world cup” moment – that aims to celebrate and scale up environmental solutions to repair the planet.

Former England and Manchester United footballer David Beckham will present one of the five awards, with each category winner receiving £1 million to develop their project.

Ahead of the event being staged on Friday evening at the MGM Music Hall at Fenway, the prince is due to meet US President Joe Biden.

But the couple’s three-day trip to Boston, which ends on Friday, has been overshadowed by the race row that saw William’s godmother Lady Susan Hussey resign as a royal aide after she repeatedly questioned a prominent black British-born domestic abuse charity boss about where she “really came from”.

A trailer promoting the Duke and Duchess of Sussex’s Netflix docuseries was released on Thursday, with the timing interpreted by some royal commentators as a snub to William and Kate.

In a black-and-white image released of Kate she is seen in silhouette walking across the stage of the theatre as an image of a cloud-filled sky is projected behind the royal.

In another image William is photographed laughing as he chats to someone off camera with broadcast equipment in the background of the picture.

Organisers of Earthshot have implemented a number of green policies, from encouraging guests to dress sustainably, from wearing vintage clothing or recycling outfits for future use, to ensuring the plants and flowers on display are grown locally.

Celebrities will walk a green not red carpet, the same used for last year’s inaugural ceremony, and it will be recycled after the event, make-up used will be predominantly vegan or certified cruelty free and all the food served will be plant based.