Prince William and Kate have concluded their visit to Boston by attending the The Earthshot Prize awards ceremony. The royal couple greeted stars including David Beckham, Rami Malek, Ellie Goulding, Annie Lennox, Catherine O'Hara, Chloe and Halle Bailey. The event recognises five winners each year for their contributions to solving environmental problems, awarding them with a £1m grant to support their work.