Princess Kate and Prince William were in great company Sunday for King Charles III coronation concert at Windsor Castle.

Their two eldest children, Prince George and Princess Charlotte, appeared to be having a blast while sitting in the royal box to watch the show with 20,000 revelers.

The family cheered along as Nicole Scherzinger took the stage to sing before Katy Perry and Lionel Richie performed for the new king and queen.

PRINCE WILLIAM, KATE MIDDLETON SHARE NEW VIDEO TO CELEBRATE KING CHARLES' CORONATION: ‘WHAT. A. DAY'

Princess Charlotte and Prince George laugh while watching coronation concert with Kate Middleton and Prince William

Princess Kate and Princess Charlotte watch the coronation concert with Prince George and Prince William. (Chris Jackson)

Prince George, fresh from his duties as a page boy to the newly crowned Queen Camilla, laughed and cheered with his father following one performance.

CORONATION OF KING CHARLES III: THE HISTORIC DAY IN PHOTOS

Princess Charlotte waved the Union Jack in support of the United Kingdom while seated beside her glamorous mother.

Their youngest son, Prince Louis, seemed to miss the concert after a big day at the coronation on Saturday.

Britain's Princess Charlotte of Wales attends the Coronation Concert

Britain's Princess Charlotte of Wales waves a Union Jack during the coronation concert. (Yui Mok/Pool/AFP via Getty Images)

Catherine, Princess of Wales, Princess Charlotte of Wales, Prince George of Wales and Prince William, Prince of Wales are seen during the Coronation Concert

Princess Kate, Princess Charlotte, Prince George and Prince William attend the king's coronation concert on May 7, 2023, in Windsor, England. (Chris Jackson/Getty Images)

Prince George and Prince William point and laugh during coronation concert

Prince George, the Prince of Wales, Prime Minister Rishi Sunak, his wife Akshata Murty put on animated display during concert as Queen Camilla watches. (Stefan Rousseau)

Princess Charlotte scratches her head during coronation concert with Princess of Wales

Kate Middleton stayed close to Princess Charlotte's side throughout the show. (Yui Mok)

The Princess of Wales sported a fiery red Alexander McQueen suit for the royal affair. 

She laughed and sang alongside her children before her husband, the Prince of Wales, gave a moving speech to King Charles III the day after he was officially crowned king.

CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER

"Pa, we are all so proud of you," William said. "I also want to express my pride and gratitude for the millions of people who serve in the forces, in classrooms, hospital wards and local communities. I wish I could mention you all. Your service inspires us, and tonight we celebrate you, too."

"I commit myself to serve you all, king, country and commonwealth," William concluded. "God save the king."

Catherine, Princess of Wales, Princess Eugenie, Princess Charlotte of Wales and Prince George of Wales during the Coronation Concert

Kate Middleton, the Princess of Wales, wore a fabulous red Alexander McQueen pantsuit for the coronation concert. ( Leon Neal/Getty Images)

Prince George and King Charles at the coronation

King Charles and Prince George are shown during the coronation ceremony at Westminster Abbey in London on May 6, 2023. (Reuters/Henry Nicholls)

The Prince of Wales wears a blue suit and tie at coronation concert

Prince William praises his father during a speech on stage at the coronation concert. (Leon Neal)

Katharine, Princess of Wales, Princess Charlotte, Prince George, Prime Minister, Rishi Sunak, Akshata Murty, Queen Camilla and King Charles III in the Royal Box during the Coronation Concert

(from front row L) Catherine, Princess of Wales, Princess Charlotte of Wales, Prince George of Wales, Queen Camilla and King Charles III cheer during the Coronation Concert at Windsor Castle. (STEFAN ROUSSEAU/POOL/AFP via Getty Images)

Queen Camilla and King Charles wear matching royal blue for coronation concert

Britain's Queen Camilla (L) and Britain's King Charles III (C) wave Union Jack flags during the coronation concert. (Yui Mok)

King Charles' coronation was held at London's Westminster Abbey on May 6. Charles and his wife, Queen Camilla, were both crowned during the official ceremony, which was attended by roughly 2,000 people.

Prince Harry and Prince Andrew, the king's brother, were both in attendance despite their tensions with the royal family.

The Duke of Sussex arrived at Westminster Abbey alone as his wife, Meghan Markle, stayed at home in California with their kids, Prince Archie and Princess Lilibet.

CLICK HERE TO GET THE FOX NEWS APP