Princess Kate enlisted the help of Lady Gabriella Windsor for her Christmas carol concert, in a very personal representation of the service’s themes of kindness, love, empathy and being there for each other through tough times.

Over the summer, Kate, 42, asked Lady Gabriella, the daughter of Prince and Princess of Michael of Kent, to join her team in creating this year’s Together at Christmas Carol service.

She gladly accepted and took on an advisory role around the music performances that featured in the service, which included Gregory Porter, Paloma Faith and Oliva Dean.

It comes after a difficult year for Ella, as she is known to her family and friends, following her husband’s shock death by suicide.

Thomas Kingston, 45, died from a shotgun wound to the head at his parents Cotswolds home on February 25.

The Royal Family have rallied around the help Ella recover from the ordeal, and in June, the King invited her to watch his birthday parade from inside Buckingham Palace in what marked her first public event since her husband’s death.

Ella’s involvement in Kate’s carol service, which celebrates empathy in the “darkest times,” is especially meaningful.

A source said: “She enjoyed her role within the service and was excited to be a part of it. The Princess was incredibly grateful for her contribution.”

Ella attended the carol service, walking in with Kate’s mother, Carole Middleton.

Speaking at an inquest in December, just days before Kate hosted her carol service at Westminster Abbey, Ella said her husband died after an “adverse reaction” to medication.

The inquest into his death was told Mr Kingston had been prescribed sleeping tablets and antidepressants after complaining of trouble sleeping following stress at work. He stopped taking medication in the days leading up to his death.

Ella said people needed to be warned about the effects of medications used to treat mental health conditions or more people could die.

She described her marriage as “deeply loving and trusting” and said her husband had never expressed any suicidal thoughts.

Princess Michael, who is known as Marie Christine, paid tribute to her son-in-law in a recent interview with Majesty Magazine, describing him as “a lovely man, so kind and so thoughtful”.

She said the family “never had an inkling that anything was wrong”.

Kate’s carol service, conducted by the Dean of Westminster and supported by the Royal Foundation, took place on December 6 and will be broadcast on ITV1 on Christmas Eve.

It marked the biggest return to royal duties so far this year for the princess, who completed her cancer treatment at the end of the summer.

Giving a personal introduction to the programme, the princess repeated the words from the letter she wrote for guests of the service, calling for “love, not fear”.

Christmas is one of my favourite times of the year, it is a time for presents, tinsel and mince pies, but it’s also a time to slow down and reflect on the deeper things that connect us all,” she says before focusing on the important messages from the Christmas story.

“The Christmas story encourages us to consider the experiences and feelings of others.

“It also reflects our own vulnerabilities and reminds us of the importance of giving and receiving empathy, as well as just how much we need each other in spite of our differences.”

Echoing the words in her video message released in September to announce she had completed chemotherapy, Kate said: “We must all shine for each other. Because in times of joy and sadness, we are all each other’s light.”

Scottish actress Kelly Macdonald narrates the service, which features three special community films which bring to life the stories of people and organisations who have inspired, counselled and comforted others in their times of need.

The first focuses on the Worcestershire Gingerbread Group, which was set up by single mum Sherisha for solo parents in order to help them tackle loneliness and build a community.

The second features six young carers aged 8-13 who go above and beyond every day to show empathy and support to their families, while the third shines a light on the incredible Sankofa Songsters.

The intergenerational choir, with members aged from two to 100, led the congregation in singing ‘Away in a Manger’ near the end of the service.

Elsewhere in the concert, Kate’s daughter Princess Charlotte, nine was overjoyed when two soloists from The Royal Ballet performed right in front of her – something the future Queen said she asked her youngest, Prince Louis, six, to keep a secret from his sister.

Downton Abbey actress Michelle Dockery gave the service’s first reading of her personal reflections on empathy and kindness, while the Prince of Wales gave a bible reading.