Kate Middleton and Prince William shared a smile during Commonwealth Day services at Westminster Abbey on Monday, March 10.

Last year, both the 76-year-old king and his daughter-in-law Kate, the Princess of Wales, missed the Commonwealth Day service as they underwent treatment for cancer but both were present for Monday's occasion, one of the major royal events of the year.

King Charles and Queen Camilla were joined by the Prince and Princess of Wales, Princess Anne, and the Duke and Duchess of Gloucester at Westminster Abbey.

The Commonwealth service began around 3 p.m. U.K. time, and upon their arrival at Westminster Abbey, the royals were greeted by members of the Shree Muktajeevan Swamibapa Pipe Band (SMSPB) from Shree Swaminarayan Mandir in Kingsbury—the world’s first Hindu eco-temple.

The Princess of Wales returned to the Family of Nations when she joined the King and Queen in celebrating Commonwealth Day. Kate missed the Westminster Abbey service last year, as did Charles, with both receiving treatment for cancer during a troubling health scare period for the monarchy.

Britain's King Charles arrived for the annual Commonwealth Day service at London's Westminster Abbey on Monday (March 10) for annual celebrations for the international organization he leads. Greenland: Why is it valuable?

Catherine, Princess of Wales, joined Britain’s King Charles III and other members of the royal family in celebrating Commonwealth Day on Monday, attending an event at London’s Westminster Abbey filled with performances from countries across the association.