Kate Middleton glows in white Catherine Walker for royal-studded Order of the Garter ceremony

It's a royal affair!

The royal family kicked off their week by attending the annual Order of the Garter ceremony on Monday morning at St. George's Chapel, Windsor. The tradition, which was founded 700 years ago by King Arthur, is considered "the oldest and most senior Order of Chivalry" in Britain.

To no surprise, this year's ceremony featured an impressive list of attendees, including Queen Elizabeth, Prince William and Duchess Kate, Prince Charles and the Duchess of Cornwall, the Countess of Wessex, the King and Queen of Spain and the King and Queen of Netherlands. King Felipe and King Willem-Alexander were installed as Supernumerary Knights of the Garter by the queen during this year's ceremony.

While the Duchess of Cambridge was there to cheer on her husband as Prince William took part in the parade, all eyes were actually on the royal mom-of-three during the royal-packed event. Kate, who made her Garter Day debut 11 years ago, stole the show in a white and black Catherine Walker coat and matching hat by Lock & Co.

The Duke and Duchess of Cambridge are also expected to step out for the 2019 Royal Ascot this week. The annual extravaganza will bring together 300,000 visitors over the course of five days, including many members of the royal family.

For more on last year's event, scroll through below.