The annual Trooping the Colour parade is one of the most important royal events on the calendar and this year it is set to be a particularly special occasion.
Not only will the historical parade on Saturday be King Charles' debut at his first birthday parade as the monarch, it will also be the first time the Princess of Wales will have her new military role.
Kate became Colonel of the Irish Guards last year, which was a position previously held by her husband Prince William, and has already this year fulfilled some of her important colonel duties, including taking part in the Irish Guards' well-known St Patrick's Day parade.
During the Trooping the Colour parade, all colonels usually wear full military uniform with some, including William and Prince Anne, even riding horseback during the ceremony, the Mirror reports.
It has been confirmed that both Charles and William will ride on horseback during the display but it has been reported that Kate will instead be travelling to Horse Guards Parade in a carriage.
According to the Daily Mail last year, Kate is also not expected to wear military uniform for the parade.
The same goes for Queen Camilla, who was recently made Colonel of the Grenadier Guards, which was a role previously held by her brother-in-law Prince Andrew who had it stripped of him along with his other royal titles.
Camilla will also ride in a carriage and will not be expected to wear a military uniform.
Trooping the Colour has traditionally marked the Sovereign's official birthday for over 260 years and Charles' appearance at the parade on Saturday will be his first as King.
On the day, over 1,400 parading soldiers, 400 musicians and 200 horses will take part in the display of military precision, horsemanship and fanfare.
The parade will travel from Buckingham Palace down the Mal to Horse Guards Parade and will conclude with a RAF fly-past, which the royals will watch from the palace balcony.
Despite Kate not having to wear the royal uniform, the princess has been seen in uniform several times in the past year during several different military engagements.
Last year, pictures of Kate on a visit to Pirbright Training Academy showed the royal spending time with the 101 Operational Sustainment Brigade at Abingdon Airfield to learn about how new recruits and serving personnel are trained.
She also participated in some of the training exercises and spent time speaking to personnel about their experiences in the British Army.
The Princess of Wales can be seen smiling in photos as she's put to the test through a number of training exercises.
She was seen sitting in a tank as well as lending a helping hand to repair some machinery.
Earlier this year, Kate joined the Irish Guards on Salisbury Plain in freezing temperatures to complete battlefield drills.
Meanwhile, also earlier this year, she joined the Irish Guards on Salisbury Plain in freezing conditions to carry out battlefield drills.
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