Interested : Kate Middleton’s Siblings Show Strong Support at Her Carol Service After Her ‘Tough’ Year with Cancer

Kate Middleton’s family wouldn’t miss her Together at Christmas carol service at Westminster Abbey, which is especially meaningful this year after Princess Kate announced that she had cancer and completed chemotherapy, which she previously described as an “incredibly tough” time.

On Dec. 6, the Princess of Wales, 42, hosted her fourth annual carol service at the famed Abbey, continuing a tradition she launched in 2021 with The Royal Foundation as a way to thank those who went the extra mile for their communities during the COVID pandemic.

Princess Kate was joined at her holiday concert by her husband Prince William and their children, Prince George, Princess Charlotte and Prince Louis. She was further supported by other loved ones from her side of the family, including her parents Carole and Michael Middleton, her sister Pippa Middleton, her brother James Middleton and his wife, Alizée Thevenet.

Related: Prince George, Princess Charlotte and Prince Louis Make First Public Appearance in Six Months: ‘It’s Been a Difficult Year’

Princess Kate is close to her parents and siblings, who all live near her in Windsor. A palace insider previously told PEOPLE that Princess Kate’s parents are “an enduring factor in the upbringing of their grandchildren,” and a support she’s leaned on this year.

“Over the years, we have climbed many mountains together. As a family, we will climb this one with you too,” James wrote on Instagram after his sister Kate announced in March that she was receiving cancer treatment.

Princess Kate and Prince William have weathered a year unlike any other amid her cancer treatment, and step outside of the spotlight to focus on her health.

“The last nine months have been incredibly tough for us as a family,” Princess Kate in the Sept. 9 video announcing she completed chemo. Prince William similarly said that it had been a “brutal” year between the cancer diagnoses of his wife and father, King Charles, while in South Africa on Nov. 7 for his Earthshot Prize Awards.

Princess Kate was further supported by her husband’s side of the family at the Together at Christmas carol service on Dec. 6, and the event was attended by Sophie, the Duchess of Edinburgh, Zara Tindall, Princess Beatrice (who’s pregnant!), her husband Edoardo Mapelli Mozzi, his son, Christopher Woolf, 8, Lord Frederick Windsor, his wife, Sophie Winkleman, their daughters, Maud, 11, and Isabella, 8. Frederick’s parents, Prince and Princess Michael of Kent, also stepped out for the night out, as did the Duke and Duchess of Gloucester.

Recently speaking about what she was looking forward to most about the Together at Christmas concert this year, Sophie said, “Beautiful music and beautiful readings. And Hors d’Oeuvres,” Hello! reported. Her comment about the course was a surprise to royal watchers, and hinted that there might be a celebration following the concert!

The royal family’s appearance at Princess Kate’s concert was especially meaningful as a show of support for her following a challenging year. The royal family was rocked when Buckingham Palace announced in February that King Charles was diagnosed with cancer, and his treatment is thought to be ongoing.

The Princess of Wales then announced in March that she was undergoing treatment for cancer, and reduced her royal duties for most of 2024 to prioritize her health. Princess Kate shared in September that she completed chemotherapy, but emphasized that she would continue to take it one day at a time.

“Doing what I can to stay cancer free is now my focus. Although I have finished chemotherapy, my path to healing and full recovery is long and I must continue to take each day as it comes,” she said in the Sept. 9 message. “I am however looking forward to being back at work and undertaking a few more public engagements in the coming months when I can.”

It was understood then that the princess was planning to host her Together at Christmas concert, and PEOPLE confirmed a few weeks later it would happen in December. Though Princess Kate hasn’t resumed the same full schedule of public engagements she once did, she has joined Prince William for unannounced outings and appeared with the royal family to commemorate Remembrance Day in November.

Kensington Palace previously announced that this year’s Together at Christmas concert themes would be love and empathy, with the Princes of Wales, 42, among those chosen to deliver readings about the theme. The palace said that 1,600 people will attend the holiday concert, welcoming those who supported people in their communities through personal relationships, work or volunteering, plus others who navigated challenges this year.

Princess Kate wrote an open letter to those attending her fourth annual Together at Christmas concert (which is also being commemorated with 15 community carol services across the U.K. during December!), sending “heartfelt thanks” for how people paid it forwards for others.

“I am so delighted that you’re able to join this Carol Service. I wanted to write and share my heartfelt thanks for all that you have done to provide comfort and hope to those who need it the most,” she said in the message.

Christmas is one of my favourite times of the year. It is a time for celebration and joy, but it also gives us the opportunity to slow down and reflect on the deeper things that connect us all. It is when we stop and take ourselves away from the pressures of daily life, that we find the space to live our lives with an open heart, with love, kindness and forgiveness – so much of what the Christmas spirit is all about.”

Princess Kate’s carol concert will later be broadcast as part of the Royal Carols: Together at Christmas program airing on ITV1 and ITVX on Christmas Eve.