The Princess of Wales is “doing really well” and has been “amazing this whole year”, said her husband as he celebrated Earthshot Prize finalists.

William praised the support he has received from Kate for his ambitious initiative rewarding environmental entrepreneurs with £1 million to scale-up their innovative ideas to “repair” the planet.

Kate is slowly returning to public duties after completing a course of cancer treatment and the prince said he hoped she would be watching and “cheering me on” when the event begins in an eco-dome in Cape Town.

The royal family will be taking part in national events marking Armistice Day this weekend and Kate is expected to attend the Remembrance Sunday service at the Cenotaph with senior members of the monarchy.

In an interview with the BBC, the prince was asked about his wife and replied: “She’s doing really well, thanks.

“And hopefully she is watching tonight.

“So cheering me on. She’s been…amazing…this whole year.

“I know she will be really keen to see tonight be a success.”

William also said he hopes his children are “proud” of the work of his Earthshot Prize, a 10-year project to boost optimism about the planet’s future and said his family was eco-conscious, minimising their effect on the environment.

The heir to the throne said they recycle, reduce their water use and turn off the lights when leaving their home, ahead of his Earthshot Prize awards ceremony being hosted by Cape Town.

Asked about what he did at home to help protect the planet, the prince replied: “Every family tries to do what they can to sort of help with the environment.

“We go through all the basics of recycling and making sure we minimise water use and turning off lights when we leave the house and stuff like that… Which is sensible in what we do around the environment.

“And I think every family has these conversations. You just try to do what you can.”

The prince went on to say: “The Earthshot Prize has got to be a bit more global than that.

“We are trying to do big-scale ambition and big-scale business to tackle some of the solutions.

“But I brought the children along that journey and tonight I hope they are watching and they are proud of kind of what we are trying to do here, which is to really galvanise that energy, that enthusiasm, to make a real impact.”

William will join about 2,000 guests in a sustainable eco-dome for the ceremony on Wednesday, which will feature stars like Heidi Klum walking its green carpet alongside the show’s hosts, Emmy award winning actor Billy Porter and TV presenter Bonang Matheba.

Young African environmentalists have been celebrated during William’s four-day visit to South Africa which began on Monday and the awards show will reflect the heritage and culture of the continent.

The prince said: “I’ve been greatly looking forward to the time I can bring Earthshot to Africa, I love this continent and spent many a year looking around, exploring it.

“And (I’m) just really thrilled to have the reception of the exuberance and energy that’s going to be in this room tonight around Earthshot in South Africa.”