Catherine, Princess of Wales, is presiding over her yearly Christmas carol concert at Westminster Abbey, with a congregation comprising members of the royal family, famous faces, and community champions who have made a difference in their neighbourhoods.
The sizable congregation will hear a selection of carols, music and readings from actors such as award-winning actors.
The focus of the service, held in the candle-lit Abbey on Friday afternoon, is kindness and showing love to others.
In the audience are Jonathan and Anna Cordiner, whose young girl was lost to a tumour, and who founded an organisation, a charity called Kayleigh's Wee Stars, to help households where there is a terminally ill child.
"The dedication, empathy, and kindness you show, often without fanfare or recognition, and without any thought of thanks or praise, make an extraordinary difference to the lives of others," wrote Catherine in a message before the festive gathering.
The princess has been making her own gradual return to official duties after her cancer diagnosis and chemotherapy, in November making her initial major address in two years, in which she reflected on recognising the "selfless, commonly overlooked efforts of carers".
Guests arriving at the Abbey can listen to budding artists aided by the Future Talent charity, co-founded by the former royal to broaden opportunities for instrumental training.
Trumpeter Carys Wood, 18, who is a trumpet player and is from Wales, has been assisted by the trust, with funding assisting with equipment, teaching, and travel fees - and she said it was "incredible" to be taking part in the evening's event.
"Music can be very expensive," Carys said. She is now enrolled at the renowned conservatoire, and added that "everyone should have the opportunity" to develop their musical skills.
Carys's 11-year-old sister, Eliza, who is a euphonium player, will also be at the Abbey. "It's unbelievable that I get to perform here in front of so many important people," she said.
Attending the service will be representatives of different generations.
That will include Saphia Turner, aged nine, honouree of a youth community award, who produces drawings and undertakes charity feats to collect donations for food banks.
The Abbey has been festooned with handcrafted festive wreaths, with celebrity baker Mary Berry and floral designer Simon Lycett contributing to their design.
Among the musical performers will be recording artist Katie Melua, the Westminster Abbey choristers and a maritime folk band from Cornwall, the Fisherman's Friends, who said the chance to take part was "the icing on the cake for us."
The festive event titled 'Together at Christmas' will be televised and shown on television on December 24th.