Wednesday marked another royal first for the Prince of Wales as he visited the 1st Battalion Welsh Guards for the first time since becoming Colonel of the Regiment.
Joined by his wife, the Princess of Wales, the couple celebrated St David's Day in Windsor one day after carrying out engagements in south Wales, where Kate and William were put through their paces during a spin class challenge. See how they got on in the clip below…
WATCH: William and Kate take on spin challenge in Wales
During the parade, William present leeks to the Officers and Guardsmen who will in turn issue it along the ranks, a traditional part of the St David's Day Parade.
The parade concluded with a march-past where His Royal Highness took the Royal Salute.
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The Prince and Princess met families from the Regiment as well as a group of troops from the 5th Royal Australian Regiment (5RAR), who are currently in the UK helping to train the Ukrainian Armed Forces.
See all of the best photos from their outing....
Kate looked gorgeous in a red coat by Alexander McQueen, paying tribute to the Welsh flag. She teamed it with black suede boots, a matching hat by Juliette Millinery, and a pair of gloves that she has owned for over 17 years!
Little royal fan Elsi-Haf Cunningham, seven, presented Kate with the flowers during the parade.
Her mother, Krystal Cunningham, 59, said her daughter will remember the experience for the rest of her life.
She told the PA news agency: "It was a very proud moment. She absolutely loves the royal family but has only ever seen Kate on TV.
"It was a big moment for her, she was a bit nervous but she was very proud to do it."
The Princess giggled as she received a traditional leek pin during the parade.
In an address to the Welsh Guards, William said: "I am both honoured and delighted to be standing here in front of you today as your new Colonel. At the same time, I'm sorry that my father couldn't be here with us here today to say farewell, but I know he would talk of his fierce pride and admiration for you all, and of his own sadness to be moving on from an appointment he held so dear since 1975."
The Prince and Princess posed for an official picture with the regiment. William recalled that his memories with The Welsh Guards Sniper Platoon Salisbury Plain are "some of my best".
The Prince: "Another key milestone in my life was also shared with the Welsh Guards, this time in the Jungles of Belize as I received my A-Level results over the Bowman Radio…
"Many of you will know the feeling of being in the jungle; you're incredibly hot, continuously soaking wet and with nowhere to hide from potentially horrendous results, it could have been a really bad day!
"Ultimately though, it was the camaraderie, the togetherness, and of course the banter of the Welsh Guards that got me through that period, and it's a time I look back on fondly."
Kate was "super impressed" as nine-year-old Thomas Lucas stole the show when he decided to perform an impromptu backflip for the Princess, catching her by surprise.
Speaking after the parade, his father Sergeant Gareth Lucas said this was typical behaviour for Thomas, calling him "non-stop".
Pointing at both of his boys, he said: "They're both into parkour now, they go to classes every week. Thomas self-taught himself backflips on YouTube - he just came home from school one day saying 'I've learned to do a backflip'".
Thomas added it was "actually quite nerve-wracking because I didn't really land it," but added that the Princess was "impressed".
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