The Princess of Wales is hosting her yearly Yuletide celebration at the historic Abbey, with a congregation comprising royals, celebrities and local heroes who have made a difference in their neighbourhoods.
The 1,600 guests will enjoy a blend of carols, music and readings from performers including award-winning actors.
The focus of the service, held in the candle-lit Abbey on Friday afternoon, is generosity and expressing affection towards one's neighbour.
Among the guests will be Jonathan and Anna Cordiner, whose young girl was lost to a brain tumour, and who set up a charity, a support fund, to aid parents with a youngster facing a life-limiting condition.
"The time, care and compassion you give, often quietly and unspoken, and without any hope for reward or acknowledgement, make an extraordinary difference to the lives of others," Her Royal Highness stated in a message before the carol service.
The Princess of Wales is continuing her own measured re-emergence to public life subsequent to her illness and medical care, recently giving her major oration since 2023, in which she reflected on recognising the "discreet, frequently unseen labour of caregivers".
Those coming to the Abbey can listen to talented youth performers supported by the Future Talent organisation, co-founded by the Duchess of Kent to broaden opportunities for music lessons.
Trumpeter Carys Wood, 18, who performs on the trumpet and is from Pembrokeshire, has been helped by the charity, with funding assisting with instruments, tuition, and transportation expenses - and she said it was "incredible" to be taking part in the evening's event.
"Pursuing music is often costly," she stated. She is now studying at the Royal Academy of Music, and added that "all people deserve the chance" to develop their musical skills.
Eliza, Carys's sister who is 11, who is a euphonium player, will likewise attend the Abbey. "I never imagined I would perform in front of so many notable figures," she said.
Among the guests will be representatives of different generations.
That will encompass Saphia Turner, aged nine, recipient of a young hero award, who creates and sells art and completes fundraising tasks to generate funds for food banks.
The Abbey has been festooned with custom-created holiday decorations, with TV cook Mary Berry and florist Simon Lycett contributing to their design.
Taking to the stage will be singer Katie Melua, the Westminster Abbey choristers and a maritime folk band from Cornwall, Fisherman's Friends, who said the invitation to sing was "the icing on the cake for us."
The Together at Christmas carol concert will be broadcast on a major network on Christmas Eve.
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