Kate Middleton and Camilla Parker Bowles are inseparable when it comes to one royal annual event.

Good Housekeeping noticed that the Duchess of Cambridge always sits beside the Duchess of Cornwall during the Trooping the Colour parade. Middleton has joined the royal family since 2011 and has earned a spot in the important parade, but she never sat next to her husband, Prince William.

In the above post, Middleton is always seated next to Camilla. According to the publication, it makes sense since both ladies are future queen consorts. However, there’s another reason why they don’t sit next to Prince Charles and Prince William.

The Prince of Wales and Duke of Cambridge join the parade in horseback alongside Prince Andrew, Princess Anne and Prince Edward since all of them have ceremonial roles as Colonels of the Household Division.

Prince William is the Colonel of the Irish Guards, one of the seven regiments in the Household Division. He received the prestigious posting before his wedding on Feb. 10, 2011.

On the other hand, Prince Charles is the Colonel of the Welsh Guards, Princess Anne is the Colonel of the Blues and Royals, Prince Andrew is the Colonel of the Grenadier Guards and Prince Edward is the Colonel of the Scots Guards. All of them report to the Colonel-in-Chief, Queen Elizabeth II.

The Queen used to ride on horseback during the Trooping of the Colour as the Head of the Armed Forces. However, in the past few years, the 93-year-old royal opted for more comfortable transportation.

In the upcoming Trooping the Colour, Prince William and Middleton’s youngest son Prince Louis would make his public debut at the Buckingham Palace balcony. Many are looking forward to the little prince because since his older siblings Prince George and Princess Charlotte made their debuts they have been a highlight of the Trooping the Colour festivities.

Prince Louis just turned 1 year old last April. Prince George was nearly 2 years old when he made his Trooping the Colour debut in 2015.

Last year, the royal children stole the show when Princess Charlotte clapped as the planes flew overhead while Prince George giggled and applaused sparingly, prompting Savannah Phillips to cover the future king’s mouth.

Kate Middleton and Camilla Parker Bowles
Kate Middleton was caught side-eyeing Camilla Parker Bowles during Prince Harry and Meghan Markle’s royal wedding. Pictured: Middleton and Camilla during Trooping The Colour on the Mall on June 9, 2018 in London. Getty Images/Chris Jackson