Princess Kate shares adorable Prince Louis moment: ‘I’m bursting’

Catherine, Princess of Wales has praised her youngest son Prince Louis for managing to keep a big secret about her Together at Christmas carols service.

Kate asked her son to keep the secret so his sister Princess Charlotte would be surprised by a ballet performance during the service.

WATCH THE VIDEO ABOVE: Princess Kate’s annual Christmas carols.

Know the news with the 7NEWS app: Download today

The nine-year-old “loves her ballet dancing” according to Kate and she did not have their inclusion in the service spoiled for her daughter.

This year marked the fourth year Kate has hosted the Together at Christmas concert at London’s Westminster Abbey, which welcomed 1600 guests to the event last Friday night (local time).

Prince Louis and Catherine, Princess of Wales attend the Together At Christmas carols concert on December 6. Credit: Max Mumby/Indigo/Getty Images

In a video shared by The Times royal editor Kate Mansey to X, the Princess was seen speaking with performers Paloma Faith, Olivia Dean and Gregory Porter behind-the-scenes.

“Louis heard me talk about the dancers over tea,” the royal explained.

“Ballet dancers?” Faith asked.

Kate confirmed: “Ballet dancers, exactly.

“So I said, ‘Louis, can you keep a secret? I want it to be a surprise for Charlotte, who loves her ballet dancing,’ and he said, ‘I won’t say anything!’

“And he’s kept the secret, this is what, maybe two weeks?

“Quite good for a six-year-old!”

But she revealed that the secret had almost popped out of him as the event drew closer.

“And then this morning he was like, ‘Please Mummy can I tell her? I’m bursting!’, ‘cause I did the (school) drop off and he really wanted to tell her,” Catherine said.

“I think, hopefully, he’s kept on with it. I don’t think he’s said anything.

“I asked her, just before we left, ‘Do you know what the surprise is?’ And she said no.”

Princess Charlotte, from left, Prince Louis and Britain's Kate, the Princess of Wales, during the Together At Christmas carol service at Westminster Abbey. Credit: Aaron Chown/AP

Kate’s fourth Together at Christmas carol service was themed around love and empathy.

Prince William, Kate and their children Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6, were seen in the front pew of the abbey for the event.

Outside the historic house of worship, the young family stopped by a “Kindness Tree” to hang messages in honour of someone in their lives who has supported them.

The abbey was decorated with festive wreaths complete with red ribbons for the 1600-strong congregation, as well as Christmas trees from Windsor Great Park donated by King Charles III.

The service highlighted extraordinary individuals who have demonstrated love, kindness and empathy within their communities.

During the festive gathering, there were readings from British actors Sophie Okonedo, Michelle Dockery and Richard E. Grant, who read an extract from A Christmas Carol by Charles Dickens.

The Prince of Wales and the Olympic gold medal swimmer Adam Peaty delivered readings.

William, The Prince of Wales, from left, Prince George, Princess Charlotte, Prince Louis and Kate, the Princess of Wales, during the Together At Christmas carol service at Westminster Abbey. Credit: Aaron Chown/AP

The service was conducted by the Dean of Westminster, David Hoyle, and featured carols sung by the Westminster Abbey choir as well as performances from Faith, Dean, Porter and others.

This year marks the 80th anniversary of the battles that led to the end of the World War II, and five veterans involved in these campaigns attended the service on behalf of the Royal British Legion. A candle was lit by D-Day veteran Bernard Morgan, a codebreaker who landed on Gold Beach on June 6, 1944.

Ahead of the carol concert, Kate penned a moving letter about love and empathy which was included with the order of service given to everyone attending. The princess wrote about vulnerability and empathy and how “in times of joy and sadness, we are all each other’s light”.

She noted that “above all else” the Christmas story “encourages us to turn to love, not fear”.

Acknowledging, perhaps, the challenges she and her family have faced since her cancer diagnosis earlier this year, the princess wrote that “love is the light that can shine bright, even in our darkest times.”

The front cover of the order of service was designed by British artist Charlie Mackesy. The illustration featured a group of people embracing each other as they stroll toward Westminster Abbey in the snow. Underneath is the question: “How did I help?” and the answer: “You were by my side. Which was everything.”

The Westminster Abbey event will be aired on television in the UK on Christmas Eve as part of a special program titled, Royal Carols: Together At Christmas.

Kate has been gradually returning to public engagements over the past few months and last week, before the carols service, she joined her husband in welcoming the Emir of Qatar to the UK during his state visit.