Kate's Christmas high fives! Princess of Wales steals the show with children who have gone 'above and beyond for charity' - including mountain-climbing six-year-old who raised £40,000 and Scouts - at the Royals Westminster Abbey carol concert

The Princess of Wales stole the show as she led the royal family at her annual Christmas carol service last night and high-fived and spoke with children who have gone 'above and beyond' for charity.

Kate crouched down to chat to seven-year-old Oscar Burrow, from Lancaster, who raised more than £40,000 for Derian House Children's Hospice in Chorley, Lancashire, by climbing 12 mountains at the age of six.

His mother Kimberley Burrow said afterwards: 'She said she'd heard about what he's done and he's doing a fantastic job, and hopes what he's doing will inspire other children to do amazing things.'

The princess was joined at her annual Christmas carol service by Prince William and children Prince George, Princess Charlotte and Prince Louis. 

The Royal children were seen stepping in to the event at Westminster Abbey - while five-year-old Prince Louis once again drew attention by blowing out his sister's candle and chatting to a statue outside.

Kate walked around the Abbey before the concert started speaking to young people who have done inspiring activities.

She knelt down and spent time speaking with seven-year-old Oscar.

The princess placed her hand on a chair and the other in her lap as she discussed his impressive fundraising efforts, watched on by his smiling mother. 

She chatted to four scouts from the 3rd Upton Scout Group in Slough her family visited during the coronation celebration weekend, part of The Big Help Out event, helping to renovate their hut.

The princess told them: 'It was really inspiring. Seriously, good job'. She then high-fived each scout in turn.

Kate, who was dressed all in white for the occasion, was pictured bending down to light Prince Louis' candle with her own.

At one point she was seen placing a reassuring hand on his back as he appeared to clutch at her coat amidst the gravity of the evening. 

As she arrived at the concert, she was seen holding Princess Charlotte's hand. 

Among the group of celebrities waiting to greet the family in the Abbey's Lady Chapel were singers Beverley Knight and Adam Lambert, musician Jacob Collier and actor Jim Broadbent.

Catherine's sister Pippa and husband James Matthews were also photographed arriving this afternoon, as were Lady Sarah Chatto and her husband Daniel Chatto.

The Princess herself unveiled a very special festive gift to guests at the concert - a rendition of Last Christmas played on John Lennon's piano.

Before the concert started, Kate met celebrities in the Abbey's stunning 16th century Lady Chapel, and chatting to Broadbent expressed her appreciation at him agreeing to read an extract from Letters From Father Christmas by Lord Of The Rings author JRR Tolkien.

She said: 'Thank you for your time because I know the lead up to Christmas can be busy for people.'

Kate appeared to joke with multi-instrumentalist Collier, who has posted music tutorial videos on YouTube, about her daughter learning the piano and he quipped 'many a plink and a plonk'.

The service began with the popular carol, Once In Royal David's City, and the congregation also heard a duet by Beverley Knight and Adam Lambert who performed The Christmas Song, made famous by Nat King Cole.

William read the passage from the Gospel according to Luke that describes how Joseph and Mary travelled to Bethlehem to be registered and the birth of Jesus.

The Abbey echoed with the voices of its choir and the congregation singing a selection of carols including Silent Night, Holy Night and Joy To The World, as well as Hark! The Herald Angels Sing.

The historic building featured Christmas trees from Windsor Great Park donated by the King, which will be given to local communities after the service.

The event will be broadcast as part of Royal Carols: Together At Christmas, a special programme airing at 7.45pm on ITV1 and ITV X on Christmas Eve, featuring additional material including an introduction by Kate and films emphasising the importance of early childhood.

The broadcast will include contributions from Rio and Kate Ferdinand, Ugo Monye, Andrea and Virginia Bocelli and Dame Sheila Hancock.

She has been loaned the iconic instrument - on which the former Beatle composed the song 'Imagine' – by the estate of the late George Michael.

The singer – who himself died tragically early, on Christmas Day 2016 - bought it in 2000 for a staggering £1.45million.

His famed Christmas hit will be performed by British Grammy award-winning singer/songwriter Jacob Collier in what will undoubtedly be the highlight of the royal service, now in its third year.

Royal Carols: Together at Christmas will be filmed tonight and broadcast on Christmas Eve on ITVI and ITVX.

Spearheaded by the princess and supported by The Royal Foundation, William and Kate's charitable organisation, it is designed to recognise those who have gone above and beyond to help others throughout the year.

The theme this year is Kate's 'early years' campaign, designed to highlight how important children's development up to the age of five is in shaping their lives as adults.

Among the 1,500 invited guests tonight were parents, carers, early educators, midwives, health visitors and community volunteers.

All have either been nominated by Lord-Lieutenants across the nation or charities associated with the Royal Family, as well as people the princess knows personally through her work in the field with her Royal Foundation for Early Childhood Centre.

Some families with young children who have had a particularly challenging year were also invited too after being nominated by charities the princess has associations with.

The service, combining traditional and modern elements, saw the Westminster Abbey choir perform alongside musicians including singers Freya Ridings and James Bey, with a special duet from Beverley Knight and Adam Lambert of The Christmas Song, made famous by Nat King Cole.

Readings were delivered by Prince Wiliam, actor Jim Broadbent, presenter Emma Willis and actor Michael Ward.

Presenter Roman Kemp introduced the special rendition of Last Christmas on Lennon's piano, talking about the role George Michael played in his own life – his mother, Shirlie Kemp, was one of his backing singers - as well as the story of the piano itself.

A source told the Mail that the instrument had been loaned by his estate who were keen to support this year's service. 

Lennon, who was killed by gunman Mark Chapman in December 1980, bought the piano in 1970 and had it delivered to studios at his home in Tittenhurst Park, Berkshire.

He composed and recorded Imagine on it the following year, and was filmed playing the song on it for the first time to wife Yoko Ono and the Plastic Ono band.

It went on to become the best-selling single of his solo career

George Michael, who subsequently composed his own music using it including the title track of his 2004 album Patience, said he bought the piano because it was 'not the type of thing that should be in storage somewhere or being protected, it should be seen by people'.

Tonight's service was also attended by the princess' family and friends.

Among the large number of royal guests were Sophie, Duchess of Edinburgh, Princess Beatrice, her stepson Christopher Mapelli Mozzi and husband Edoardo Mapelli Mozzi, Princess Eugenie, Zara Tindall and Peter Phillips and his daughters Savannah and Isla.

Although he was not present due to a diary clash, the King has donated Christmas trees from Windsor Great Park to decorate Westminster Abbey, which will be donated to the local community after the service.

The abbey will also be filled with sustainable, eco-friendly festive decorations.

Outside the princess has had a special post box installed, with guests encouraged to bring a card which will be distributed to children who might be struggling this year through charities including Child Bereavement UK, East Anglia Children's Hospice, Evelina London and the British Red Cross.

They will also be greeted by carols and Christmas songs by the Action for Children Young Carers Aloud Choir, made up of 12 young carers aged six upwards.

A royal aide said the princess – who will not speak on the night but will feature in a pre-filmed introduction to be broadcast on Christmas Eve – hoped the service would remind people of 'how precious' the early years of a child's life at a time when the world celebrates the birth of a newborn baby.

'It is a reminder of how unique this time is, and how precious those early years are, as we start to form our very first relationships, bond with those closest to us, and explore the world in which we live,' they said.

'It also signifies hope. As we look to the future, we hope our children will grow up in a happier, healthier, fairer, kinder and more tolerant world. A world based on love and compassion.

'This evening, Westminster Abbey will be filled with more than 1,500 inspiring people in appreciation of their selfless support as they work tirelessly to help the youngest members of our society to flourish.'

Royal Carols: Together at Christmas will air on December 24 at 7.45pm on ITV1 and ITVX