The Duke and Duchess of Cambridge led a minute’s silence to pay respects to the New Zealand terror attack victims, at a St Patrick’s Day parade.
William, who is Colonel of the Irish Guards, and Kate were visiting 1st Battalion at their base in Hounslow, west London.
The parade began with the Last Post, before a minute of silence was observed by the royals, the Irish Guards and their families who stood in memory of the 50 victims.
The sun shone as Kate, wearing a dark green Alexander McQueen coat and hat from Lock and Co, then handed out baskets of shamrock.
Watching close behind was her husband in his Irish Guards Frock Coat in the rank of Colonel.
After Kate presented the shamrock to officers and warrant officers, three cheers were raised to the royal duo before a march past where William took the salute.
Some 350 soldiers marched on the Parade Square at Cavalry Barracks on Sunday morning.
Their families proudly watched on wrapped up warm with blankets to protect from the cold March wind.
Leading the procession was Irish wolfhound and mascot Domhnall, whom Kate patted and stroked several times while presenting him with a shamrock.
Drummer David Murray, his regimental handler, said the St Patrick’s Day parade was “number one” in his calendar and like a “second birthday”.
The mascot, wearing a red coat, was presented with his first shamrock in 2013 and today led the regimental band and parade.
Drummer Murray said: “We’ve had a week-long preparation as a battalion, we’ve had a couple of rehearsals, couple of little bits that we’ve had to obviously fine tune.
“Domhnall – he’s been in the battalion since 2012, he’s pretty good at his job… doesn’t really need to fine tune much so in regards to me and him it’s been quite a smooth week.”
He added: “He helps me through the parade to be honest, he knows what he’s doing.”
Kate was then presented with posies of flowers by six-year-old Jemima and her sister Athene, three.
Crouching down to speak to them, she waved goodbye to the siblings before Kate cooed over their 12-week-old baby brother, Rory.
“Is he a good sleeper?”, she asked his father, Major Ben Irwin-Clark, company commander of number two company.
“Oh well enjoy, it just gets better and better,” she added, imparting some maternal wisdom as she waved goodbye.
Ryan Orr, who has been with the Irish guards since 2004, brought his six-year-old son Kallum to the parade.
It is Kallum’s second parade, having met William and Kate in 2016.
The recruitment warrant officer, who lives in Aldershot, joked: “He put his hand in Prince William’s pint three years ago, didn’t you sausage?”
Asked if he was proud of his dad, Kallum said “Yeah, extremely”, adding that he was looking forward to meeting the duchess again.
The family later shared a laugh with Kate and William as they recounted the episode.
Mr Orr said: “It means a lot because every (St Patrick’s) day we get together… have a good drink and a catch up at the same time.
“The battalion’s due to deploy to South Sudan and Iraq this year so it’s extra special to get together as one before they deploy.”
Kate and William later sipped Guinness as they were toasted by hundreds of guardsmen.