Catherine, Princess of Wales, is presiding over her customary Christmas carol concert at the iconic London venue, with guests including members of the royal family, famous faces, and community champions who have supported their local areas.
The sizable congregation will enjoy a blend of carols, music and readings from performers including award-winning actors.
The focus of the service, held in the atmospheric historic church on the afternoon, is kindness and showing love to others.
Among the guests will be Anna and Jonathan Cordiner, whose young girl was lost to a brain tumour, and who set up a charity, a support fund, to support families who have a child with a terminal illness.
"Your efforts, love, and understanding, often discreetly and without words, and without any thought of thanks or praise, make an remarkable change to the circumstances of individuals," the Princess expressed in a message before the festive gathering.
The princess has been making her own steady comeback to public life after her cancer diagnosis and chemotherapy, last month delivering her major oration since 2023, in which she talked about recognising the "selfless, commonly overlooked efforts of carers".
Guests arriving at the Abbey can listen to budding artists aided by the charitable trust Future Talent, co-founded by the late Duchess of Kent to broaden opportunities for instrumental training.
Carys Wood, aged 18, who performs on the trumpet and is from southwest Wales, has been assisted by the trust, with funding assisting with musical instruments, lessons and travel costs - and she said it was "incredible" to be performing at the concert.
"Pursuing music is often costly," the musician remarked. She is now studying at the renowned conservatoire, and added that "everyone should have the opportunity" to cultivate their performance abilities.
Eliza, Carys's sister who is 11, who plays the euphonium, will be present at the Abbey. "It's unbelievable that I get to perform here in front of so many distinguished guests," she said.
Within the audience will be individuals spanning multiple eras.
That will include Saphia Turner, aged nine, winner of a prize for youthful altruism, who creates and sells art and completes fundraising tasks to collect donations for community pantries.
The Abbey has been festooned with handcrafted festive wreaths, with well-known chef Mary Berry and flower expert Simon Lycett contributing to their design.
The musical lineup includes Katie Melua, the Westminster Abbey choristers and a Cornish sea shanty group, Fisherman's Friends, who said the opportunity to perform was "a dream come true."
The Together at Christmas carol concert will be televised and shown on ITV1 on Christmas Eve.
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