Prince Louis apparently kept a surprise secret from his big sister ahead of the Princess of Wales's Together at Christmas service

There were several key takeaways from Kate Middleton’s Christmas carol concert, including Prince George and Prince Louis’s resemblance to their dad, Prince William, and Princess Catherine’s super-telling body language.

Princess Kate spearheaded the Together at Christmas carol service with The Royal Foundation in 2021 as a way to thank those who gave back to their communities during the COVID pandemic, and it's continued as a tradition ever since, becoming a staple on the royals' annual calendar.

While at the “Together at Christmas” celebration at Westminster Abbey on Dec. 6, Princess Kate revealed why she was so proud of her 6-year-old son, Prince Louis. Kate attended the annual holiday celebration alongside her husband, Prince William, and their three children: Louis, Princess Charlotte and Prince George.

Princess Charlotte earned comparisons to her late grandmother Princess Diana at the annual ‘Together at Christmas’ carol service

On Dec. 6, Prince William escorted the couple's three children to Westminster Abbey in London for Kate's fourth annual carol service. The outing marks the first time the trio of siblings have made a joint public appearance since Trooping the Colour in June.

Catherine, Princess of Wales, hosted the 'Together at Christmas' carol service, and Prince Louis helped her with a surprise for Princess Charlotte.

Prince George appeared to be keep a protective eye on his younger brother during their mother's biggest event of the year.

Prince Louis may be young, but he already knows that the holidays are all about spending time with family. The six-year-old prince joined his family last Friday for the Princess of Wales' annual 'Together at Christmas' carol service.