Prince William, King Charles attend Garter Day service without Kate Middleton

Prince William and King Charles attended the Garter Day service at Windsor Castle but Kate Middleton was not present with them.

Father and son, along with Queen Camilla and other members of the royal family, attended the traditional celebration marking the ancient Order of the Garter this afternoon, kicking off the busy royal summer season. 

This beloved event follows closely on the heels of the King's birthday parade, Trooping the Colour, where Kate made her highly anticipated first public appearance since disclosing her cancer diagnosis.

Despite her return, Kate's ongoing treatment means she is not yet resuming full-time royal duties. 

According to royal sources, her public engagements will be based on how she feels at any given time. Today's Order of the Garter ceremony and the upcoming Royal Ascot festival, starting tomorrow, are not included in her current duties.

In a statement on Friday, Kate said that she "hopes to join a few public engagements over the summer". She explained: "I am learning how to be patient, especially with uncertainty. Taking each day as it comes, listening to my body, and allowing myself to take this much-needed time to heal."

Today, the royal who are Ladies and Knights of the Order of the Garter – the country's oldest and most senior Order of Chivalry – processed down the hill from the Berkshire castle's State Apartments to St George's Chapel, dressed in white plumed hats and dark blue velvet robes, watched by crowds of onlookers, which included Sophie, the Duchess of Edinburgh, who in other years is joined by Kate After the ceremony, Charles, Camilla and members of the royal family departed by carriage and returned to the castle.

Other royals in the order include Princess Anne, Prince Edward, the Duke of Kent, the Duke of Gloucester and Princess Alexandra. Prince Andrew is also a member but like last year, was not among those in the parade.