The Queen enjoyed a Christmas carol performance on the steps of her Windsor Castle home – as she welcomed the Duke and Duchess of Cambridge after their royal train tour of the country.
As a Salvation Army band played festive tunes for the Queen and her family gathered around her, the head of state could be seen quietly singing along.
The monarch's appearance was the first time she has been seen in public with senior members of the royal family en masse since before the coronavirus pandemic.
The Prince of Wales and Duchess of Cornwall stood socially distanced nearby, as did William and Kate, the Earl and Countess of Wessex and the Princess Royal with Christmas trees lit with lights nearby, adding to the atmosphere.
The Cambridge's trip to thank key workers, volunteers and communities for their pandemic efforts has provoked veiled criticisms from Welsh and Scottish ministers, who raised suggestions about the timing of the visits while Covid cases were still prevalent and many parts of the UK were subject to strict Covid rules.
But Prime Minister Boris Johnson believes William and Kate's tour, which has covered 1,250 miles over three days, was a "welcome morale boost", No 10 said, after Downing Street officials initially refused to say it complied with coronavirus restrictions.
At the end of the performance the Queen, wearing an Angela Kelly, hat and coat in Christmas red and a ruby and diamond spray brooch, chatted to her family in turn and as she turned to walk up the steps back inside the castle William said "Bye gran".
Commissioners Anthony and Gillian Cotterill, territorial leaders for The Salvation Army in the UK and Republic of Ireland, also came forward to speak to the Queen who told them "nobody's allowed to sing anymore".
Choirs are allowed to perform in the open air and Anne told her mother "Oh, we can sing outside".
Mr Cotterill said afterwards: "The Queen was saying she was just so happy we were able to play some carols because she thinks this will be the only time she'll be able to hear carols, and she was disappointed we didn't sing. "
Sometimes we're playing musicians and other times we're a choir, at an event like this it's better to have the band as you can hear it for miles."
The Salvation Army's Regent Hall Band, based in London's busy Oxford Street, played Hark The Herald Angels Sing and The First Noel for the royal family.
Mrs Cotterill added: "I did see the Queen mouthing some of the words – so that was nice."