The Prince and Princess of Wales stepped out for a joint engagement to celebrate St Patrick's Day with the Irish Guards on Friday.
It marked Kate's first time attending the parade as Colonel of the regiment, having recently visited the 1st Battalion Irish Guards on Salisbury Plain.
WATCH: The moment Princess Kate hands out shamrocks to the Irish Guards
The Princess has taken over the role from her husband, Prince William, who is now Colonel of the Welsh Guards.
See all of the best photos from their joint engagement, including their emotional speeches...
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Kate presented the traditional sprigs of shamrock to the officers and guardsmen, who will in turn issue it along the ranks, as well as to the Irish wolfhound regimental mascot.
MORE: Princess Kate's St. Patrick's Day outfit was surprisingly different - here's why
Kate made sure to make a big fuss of Seamus.
The Princess looked stunning in a bespoke teal button-up coat with a matching hat by Jane Taylor. She also sported her gold shamrock brooch, which is loaned out to royal ladies associated with the regiment.
She also accessorised with her diamond and emerald drop earrings.
It marked a historic occasion for Kate who took the salute for the first time in her new role as Colonel of the Irish Guards.
In an emotional speech, outgoing Colonel William said: "Whilst I am extremely happy to be here celebrating St Patrick's Day with you once again, I'm incredibly sad to be giving this speech, as it really does mean my time as your Colonel has come to an end.
"It has been one of the great honours of my life to hold that title; I'm proud of everything it stands for – just as I'm immensely proud of every single one of you."
He added proudly: "I may be stepping aside, but in Colonel Catherine you have a committed, focussed, and already incredibly loyal 11th Colonel.
"As you serve together over the years ahead, know that I will continue to watch you, with huge pride in having been one of you."
Kate said it is a "true honour" to be the regiment's Colonel in her address. She pledged: "I am here to listen to you, to support you, and to champion you in all you do – this is a responsibility I do not take lightly."
She continued: "Last week, I took the opportunity to visit some of you on Salisbury Plain, to see your inspiring work for myself.
"The day was bitterly cold, and while displaying your skills to yet another visitor was probably the last thing any of you wanted to do, all I saw was enthusiasm, pride, and incredible dedication. I was hugely impressed with your insistence that nothing is as bad as it seems, and – most of all - your boundless, irreverent, glorious sense of humour."
Paying tribute to her husband, the Princess said: "I look forward to spending more time with you and your families, seeing your commitment to duty and service in all you do.
"Before I close, however, I want to thank Colonel William. He has always talked about his fierce pride for this Regiment. I know he will continue to support us all in the work we do. Finally, I would like to wish you all, a very happy St Patrick's Day."
The couple appeared to get the giggles as they posed for a group photo with the Irish Guards. William was dressed in a Blues Jumper, Frock Coat and Sword for the parade.
Keeping out of the rain, the Princess was gifted posies by Aoife, six, and Alice, four, daughters of Warrant Office Second Class Alistair Wigley.
Crouching down, she said, "Thank you" and "You both look gorgeous".
The Perince and Princess were greeted with three cheers in the raucous Junior Ranks dining hall where the Senior Guardsman in the Battalion proposed a toast to Their Royal Highnesses with Guinness.
William sipped from a pint glass, while new Colonel Kate held a half-pint of the back stuff - as soldiers drank from cans of Fosters and Guiness.
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