King Charles, Queen Camila mark Commonwealth Day with William, Kate

King Charles and Queen Camila are celebrating the 56th Commonwealth Day with the future king and queen.

On Monday, March 9, Their Majesties The King and Queen were joined by Prince William and Kate Middleton as the royals gathered at the annual cultural celebration at Westminster Abbey, London.

The monarch shared several snaps from the annual celebrations on his official Instagram account and talked about "the defining strength of the modern Commonwealth."

The caption read, "The King and Queen, joined by The Prince and Princess of Wales, The Princess Royal and The Duke and Duchess of Gloucester, have attended the Commonwealth Day Service of Celebration at Westminster Abbey."

"The service drew on this year’s Commonwealth Day theme ‘Accelerating Partnerships and Investment for a Prosperous Commonwealth’, celebrating collaboration as the defining strength of the modern Commonwealth."

Charles also posted a special message for all the members of the Commonwealth on Sunday.

He wrote, "We join together on this Commonwealth Day at a time of great challenge and great possibility. Across our world, communities and nations face the increasing pressures of conflict, climate change and rapid transformation. Yet it is often in such testing moments that the enduring spirit of the Commonwealth is most clearly revealed.”

“Working together, we can ensure that the Commonwealth continues to stand as a force for good - grounded in community, committed to the kind of restorative sustainability that has a return on investment, enriched by culture, steadfast in its care for our planet, and united in friend."