Kate Middleton attends surprise Christmas tea party in sneak peek of carol concert broadcast

London: The Princess of Wales, 41, recently amazed a group of families who were gathering at the end of the year. Princess Kate took time to thank some inspiring adults who have helped shape children’s lives.

The celebration will appear in a film as part of her Royal Carols: Together At Christmas concert broadcast on ITV on Christmas Eve, and three shots from behind the scenes of the bash, which was filmed last month in London, have been released.

The carol service held at Westminster Abbey on Dec. 8 highlighted the vital importance of early childhood and Kate used the occasion to thank those among the 1,500-strong congregation for the help and support they are giving to the youngest in society.

Princess Kate’s early years campaign, Shaping Us, focuses on enhancing understanding and supporting children in their first five years of life. But that can’t happen without help from family members or professionals.

So, at the Christmas party, Kate learned more about how the adults are making incredible contributions to raising the next generation.

One of those was Ray, who comes from a familiar place for the Princess — he works as a music therapist at East Anglia’s Children’s Hospices, of which she has been a patron since she started in her public life more than a decade ago. Ray has helped support the family of Henry, 10, (who joined the party with his brother George, 12) who was diagnosed with Spinal Muscular Atrophy at 18 months old.

The Princess of Wales also spent time with Brenda, who is a retired mental health nurse from Sussex in southern England. She volunteers in local schools helping children like Jenson, 8, who Kate met, develop new skills like reading through the local intergenerational program.

Another guest was Russell Gray, who is a soccer coach in Manchester, and he met Kate with Rico, 13. The soccer coaching has helped build Rico’s confidence and helped him to pursue his passion for the sport.

As well as highlighting the Shaping Us campaign, Kate used the third annual carol concert to pay tribute to professionals in the sector, and many were invited to the big event at Westminster Abbey.

Among those was Pauline Byrne, center manager for Baby Basics in Barry, south Wales, who told PEOPLE, “She has an aura about her. She has come from a very family-orientated background and if you have had that sort of upbringing you appreciate it more.”

In the run-up to the holidays, Kate was also inspired to bring her three children, Prince George, 10, Princess Charlotte, 8, and Prince Louis, 5, to a donation center not far from their home in Windsor to lend a hand with volunteering. The Princess of Wales and her kids packed toys and clothing for families in need this holiday season.

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“She has a lot of empathy and compassion. I think she doesn’t take her life for granted,” Byrne tells PEOPLE. “She must recognize that there are families who are not as fortunate and that your surroundings and resources actually shape how you develop in your adult life.”

The short film featuring the surprise Christmas tea party is part of the broadcast Royal Carols: Together at Christmas, airing on Christmas Eve at 7:45pm on ITV1 and ITVX in the U.K.