In an interview with a radio station at the Royal Marsden Hospital, William was asked about his top festive traditions by children receiving cancer treatment at the London hospital, of which he has been president since 2007.
One young patient asked the Duke of Cambridge what he would do if he could play Santa for one day.
"I think I'd have to make sure everyone could enjoy it," he replied.
"So we’d have to bring everyone together have a big party.
"And there would definitely be no Covid and there certainly wouldn’t be any cancer in the world if I was in charge of Christmas for the day.”
The interview was particularly poignant as it came shortly after his grandmother the Queen cancelled the family's traditional pre-Christmas lunch next week amid a rise in Covid-19 cases.
When asked what he wanted by another child for Christmas, Prince William said he wanted Aston Villa to win their football match on Boxing Day.
Another child wanted to know if the Duke had a Lamborghini, to which he replied: “I would love to have a Lamborghini – a big, bright yellow Lamborghini.
“But no, unfortunately, I don’t have a Lamborghini – I’m going to have to save up for one of those when I get older.”
William also revealed to the radio station for the hospital - which specialises in cancer treatment - that he watches the "very funny" film Elf, starring Will Ferrell, every year, while Feliz Navidad is his favourite Christmas song.
“I could say Mariah Carey… as well, it’s a good one, and obviously there are many others but I think I’ll probably go for Feliz Navidad – it’s a bit more jolly," he added.
He added that food is "quite important" to him during the festive season and admitted he "loves" Brussels sprouts and other Christmas veg.
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"I do tend to eat a lot at Christmas," said the Duke.
"There’s always a tiny little bit of space left in my stomach somewhere for a bit more turkey or sausage or, you know, a bit of wine.”
He also said that “bringing the family together at Christmas time is always lovely” and that having children made it “a whole different ball game of noise and excitement”.
Playing board games Monopoly and Risk with his children - George, eight, Charlotte, six, and three-year-old Louis - is also a firm favourite on December 25 at Kensington Palace, said William, adding that he liked ice-skating but was not very good at it and described his skills as a “deer on ice”.
William also paid tribute to the patients and staff at the hospital, saying: “I’ve always been amazed by the positivity, the energy and the hope and the love that goes with the Royal Marsden.”
He said staff would ensure the festive period would be “jolly” despite it being “a different Christmas for those in the hospital this year”.
Most years, the Queen invites her children, grandchildren and great-grandchildren to join her at Buckingham Palace before she departs for her annual Christmas stay at Sandringham.
But this year, like last, plans were cancelled amid concerns over a spike in Covid cases due to the surge in the Omicron variant.
Plans were reportedly fully in place at Windsor Castle for next Tuesday’s Christmas lunch, which the 95-year-old monarch hosts each year for her extended family.
It is understood the decision was a precaution, with a Buckingham Palace source suggesting it could put too many people’s Christmas arrangements at risk if it went ahead.