Kate Middleton Is ‘Incredibly Grateful’ for Lady Gabriella’s Help with Her Christmas Carol Service Gabriella marked her first Christmas without late husband Thomas Kingston by assisting Kate with ‘Together at Christmas’

The Princess of Wales, 42, wanted the fourth annual service to be focused around love, kindness and empathy — and she asked Lady Gabriella Kingston (née Windsor) to join her team to help, PEOPLE confirms.

Gabriella, the only daughter of Prince and Princess Michael of Kent, played an advisory role around the music performances featured in the Dec. 6 service, PEOPLE understands.

And the 43-year-old royal, who works as a freelance journalist, enjoyed her role and was excited to be a part of the service, a source tells PEOPLE.

Gabriella’s role in the service was fitting for the royal, who previously showed off her musical chops in 2020, when she released two songs to benefit music nonprofit Playing for Change Foundation.Gabriella’s role in the service was fitting for the royal, who previously showed off her musical chops in 2020, when she released two songs to benefit music nonprofit Playing for Change Foundation.

In addition to her role in planning it, Gabriella also attended the festive, candle-lit event — which was held at Westminster Abbey on Dec. 6 and airs on Christmas Eve on ITV1 and ITVx in the U.K — along with Princess Kate, Prince William, and their kids, Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6.

The royals gathered at the London church to watch traditional hymns and songs and readings led by the Prince of Wales, Richard E. Grant and more stars, as well as musical performances by guests including Olivia Dean and Paloma Faith. The event also featured a piece by pianist Rosey Chan and a performance by two soloists from The Royal Ballet and students from The Royal Ballet School.

Set to air on Christmas Eve, the Together at Christmas service — which welcomed a total of 1,600 guests, including members from both sides of Kate’s family — marks the end of a difficult year for Princess Kate, who announced she was undergoing treatment for cancer in June.