The Queen took a walk down the Millennium Stadium tunnel to present the Royal Welsh regiment with their new colours in a military ceremony full of pomp and grandeur.
Clad in sky blue, the 89-year-old strode onto the pitch – which has graced the likes of rugby stars like Sam Warburton, Jonny Wilkinson and Jonah Lomu – and was met with loud cheers from an 8,000 strong crowd.
Today's Cardiff ceremony was the final formal recognition of The Royal Welsh – which formed in 2006 after the merger of the Royal Welch Fusiliers and the Royal Regiment of Wales.
The event certainly seemed to please the Queen who called the large military parade "excellent" and "terrific" before meeting local dignitaries and army personnel and veterans in the home team dressing room.
And in an address to the stadium crowd, she said: "It gives me great pleasure to present these new colours to the battalions of the Royal Welsh here in the Millennium Stadium and to see so many of the regiment, your friends and families and the Comrades Associations gathered to witness and to enjoy this occasion.
"As your colonel in chief, I am also delighted to know that the City of Cardiff has granted the regiment the freedom of the city.
"This generous honour typifies the support that the people of Wales have given to its regiments over the years and I know this enduring link has been a great source of strength and encouragement, especially so during the regiment's recent operational deployments to Iraq and Afghanistan
"These operations were conducted in the most testing of circumstances and it is with considerable pride in you that I say that you rose magnificently to the challenges that you faced, in the way that your forebears have always done, with conviction, good humour and courage.
"The values and ethos which you espouse are embedded within the fabric of these colours and I trust that they will continue to provide confidence and inspiration to you and your successors."
Today was only the second time the Queen has graced the stadium – after she made her "debut" at the rugby World Cup final in 1999 to hand over the William Webb Ellis trophy to winners Australia.
The Queen arrived in the Welsh capital via royal train before being driven the short distance to the 74,500 capacity ground in a £10 million custom made burgundy Bentley state limousine.
While she was in transit, hundreds of soldiers from the Royal Welsh marched through the streets of Cardiff – drawing large crowds in the process.
Regimental adjutant of The Royal Welsh, Captain Ben Phillips, said the Millennium Stadium was a fantastic venue for such an occasion.
"As military parades go this will almost certainly be one of the best examples of Welsh pride and support for military forces in Wales," he added.
And that view was also shared by Welsh Rugby Union chief executive Roger Lewis.
Mr Lewis, who has seen the the national side win three Grand Slams while at the helm for the past nine years, said: "We were thrilled that the Royal Welsh wanted to use the Millennium Stadium for such a historic occasion.
"There have been some big names walking down the tunnel since the stadium was built, but I think the Queen may even surpass them all."
The event got off to a bang with the Royal Welsh's military band in full swing – as soldiers were led out by regimental mascot, Lance Corporal Shenkin the goat.
After inspecting the troops in an open top Range Rover, the Queen lifted up the new flags of the regiment.
Curator of the regimental museum of The Royal Welsh in Brecon, Richard Davies, said the day was an important milestone.
"It's a lot to do with the heritage and tradition of the army. The presentation of the colours events relate directly to the specific regiment's sense of itself, its history and its own past," he added.
And following rousing renditions of God Save The Queen and the Welsh national anthem Hen Wlad Fy Nhadau (Land Of My Fathers), the monarch met a number of dignitaries including serving and former members of the regiment.
Paul Davies, 52, of Bargoed, south Wales, said he and wife Lorraine, 53, were overjoyed to chat with the Queen.
Mr Davies, who served with the Royal Welsh Fusiliers between 1978-1986 before he broke his neck in training, said: "It's really good to see the schools here and the children. This is how they know what's going on today. The most emotional bit of the ceremony was when the old colours were marched off."
Lance Corporal Carl Trantor, 27, from Bangor, shared a joke with the Queen about his time last week at the supposedly haunted Tower of London.
"She asked jokingly if I had seen any ghosts but I said not on my watch," he laughed. "It was amazing honour. It's the pinnacle of my career to date."
The Queen was wearing a sky blue cashmere coat by British designer Stewart Parvin and an Angela Kelly hat.
The lunch menu included organic salmon, Welsh lamb, Pembrokeshire potato fondant and Halen Mon salted caramel cream.
Before making her way back to Buckingham Palace, the Queen was given a bunch of posies by six-year-old Maisie Gregory.
After she handed over the flowers, a private, raising his hand to salute the Queen, accidentally hit the youngster on the head.
While the Queen did not notice as she left, the red-faced soldier turned round to apologise to Maisie and her mother Joanne Gregory.
Mrs Gregory, who is the wife of Regimental Sergeant Major Martin Gregory, said that despite the mishap it had been a proud day for her family.