ITV News Royal Editor Chris Ship reports from the London Palladium
Speaking ahead of a special panto performance at the London Palladium - staged in honour of key workers during the coronavirus pandemic - William said: "I want to pause and pay tribute to a true national treasure, Dame Barbara Windsor, who so sadly passed away last night."
He added: "She was a giant of the entertainment world, and of course a legend on pantomime stages across the country, including here at the London Palladium.
“And I know we’ll all miss her hugely.”
In the first red carpet engagement as a family of five, William and Kate arrived with their three children Prince George, Princess Charlotte and Prince Louis to watch a performance of Pantoland – staring Julian Clary, Elaine Paige and a host of stars.
The children, who appeared apprehensive when they arrived, relaxed and looked on with glee as they took their seats in the royal box.
William added: “We are here tonight for a very special performance. Special, because of you – the key workers here in the audience.
“You include community workers, volunteers, teachers, NHS staff, representatives from the emergency services and military, researchers working on the vaccine, people helping the homeless, those manning vital call centres, and staff from a wide range of frontline charities – to name but a few.
“You have given your absolute all this year, and made remarkable sacrifices.”
Earlier this week the duke and duchess travelled 1,250 miles around the country, during a three-day tour on the royal train, to thank frontline and key workers, communities and individuals for their efforts during the pandemic.
When William returned to the box, there was a swift shuffling of seats, as the duke sat between his eldest son and daughter as Louis sat on Kate’s lap.
Guests were encouraged to wear a Christmas jumper and while Kate wore a dress by Alessandra Rich, William had on a festive red pullover.
When the Cambridges first arrived George, aged seven, Charlotte, aged five, and two-year-old Louis stopped briefly to watch actors dressed as elves entertaining the guests on the red carpet.
The young royals were photographed meeting Sir David Attenborough at their Kensington Palace home in September, when he came to watch his new film with their father.
And the children also went to see Kate’s garden at the Chelsea Flower Show last year.