In their first international trip since becoming Prince and Princess of Wales, William and Catherine will visit the US this week for an environmental prize.
The royal couple will show their support for finding ways to tackle climate change, at the second annual Earthshot Prize awards in Boston.
Environmental campaigner Sir David Attenborough will also be contributing.
The awards were launched by Prince William last year and the three-day trip to Boston will be his first big international appearance since becoming Prince of Wales.
As well as the prize ceremony on Friday, Prince William and Catherine will be on show in front of the US public, which in recent months will have seen much coverage of the Royal Family, ranging from the Queen's funeral to the Netflix drama The Crown, to stories about Prince Harry and Meghan.
Prince William will be seen as taking on the environmental mantle from his father, King Charles. But he will also be setting out his own stall, showing how much he wants to engage in green issues.
He will want to move the US royal coverage away from the gossip pages and on to more serious matters, using the days before the award to visit projects for the disadvantaged in Boston, and to see green technology schemes.