Prince William, Kate appear at Garter Day as Queen Elizabeth II, Prince Andrew skip public events

Members of Britain's royal family stepped out Monday for Garter Day, marking the first time the annual tradition has returned since the start of the coronavirus pandemic.

Prince Charles and Camilla, Duchess of Cornwall, and Prince William and Kate, Duchess of Cambridge, were among the royals who publicly attended Garter Day celebrations, a day of pomp and pageantry that includes a procession around Windsor Castle.

Garter Day, celebrated annually on June 13, is the day new appointments are invested in the Order of the Garter, which was created by King Edward III in 1348 and is the "oldest and most senior Order of Chivalry in Britain," according to the royal family's website.

Absent from the public celebration of the day was Queen Elizabeth II, who has been suffering from mobility issues that caused her to miss several events during her Platinum Jubilee celebrations earlier this month.

The 96-year-old queen attended the Garter Day investiture and lunch privately, but did not attend the public procession to St. George's Chapel at Windsor Castle nor the service.

Buckingham Palace later released a photo showing Elizabeth standing in between Prince Charles, the heir to the throne, and Camilla, both of whom were dressed in their Order of the Garter ceremonial dress.

Camilla was made a Royal Lady of the Order of the Garter Monday, part of her journey to becoming queen consort when the queen dies and Charles becomes king.

Joining the queen in not attending Monday's public events was her second-oldest son, Prince Andrew, who is a member of the Order of the Garter.

A royal source told ABC News the last-minute change of plans for Andrew to not attend public events was a "family decision."

In February, Andrew agreed to settle a sexual assault lawsuit in which a woman, Virginia Giuffre, alleged that Jeffrey Epstein trafficked her to the prince, who she claimed took advantage and sexually abused her when she was under 18.

Prince Andrew repeatedly denied the allegations and attacked Giuffre's credibility and motives.

One month earlier, in January, Andrew lost his military titles and royal patronages amid the lawsuit.

Buckingham Palace announced at the time that Andrew's titles and patronages were returned to his mother, the queen.

"With The Queen's approval and agreement, The Duke of York's military affiliations and Royal patronages have been returned to The Queen," the palace said in a statement. "The Duke of York will continue not to undertake any public duties and is defending this case as a private citizen."

Andrew did not attend any of the queen's Platinum Jubilee celebrations earlier this month because he tested positive for COVID-19, according to a spokesperson.

The last public royal event Andrew attended was in March, when he attended a service of Thanksgiving for his late father, Prince Philip, at Westminster Abbey.