The Duke and Duchess of Cambridge have honoured the Irish Guards in London before travelling to France for a two-day visit.
Prince William, who is Colonel of the Irish Guards, and Kate visited the 1st Battalion Irish Guards at their base on Friday morning to present them with shamrocks during a parade to mark St Patrick's Day.
The Duke and Duchess, in dark green coat by Catherine Walker decorated with her Irish Guards brooch, were celebrating at the annual parade at the barracks in Hounslow, west London.
The Duke stood at his wife's shoulder on the parade ground as she handed out sprigs of shamrock to the Irish Guards, according to decades of tradition.
Led by their mascot, the Irish Wolfhound Domhnall, the 450 1st Battalion Irish Guards marched onto the Parade Square at Cavalry Barracks.
Four-year-old Domhnall prepared for his moment in the spotlight with a breakfast of three boneless chicken thighs for breakfast and a five mile walk, and was wrapped up in a scarlet coat.
Handler drummer Adrian Cathcart, 29, from Ballymena, Northern Ireland, said: "He's taking it all in his stride."
The Royal couple then met with members of the regiment and their families, enjoying a toast at the Guardsman's lunch before making their way to a private charter plane to fly to Paris.
Video taken inside the barracks showed that the Duchess was somewhat less enthusiastic about her pint of Guiness than some of the soldiers.
Later, the Duke and Duchess will be received with an official welcome from President Francois Hollande in Paris, before a glittering black tie dinner designed to celebrate the relationship between Britain and France.
On Saturday, the Royal couple are due to attend Les Invalides, where victims and first responders from the Bataclan terror attack will share their stories.
The Paris trip comes after a difficult week for the Duke, who has been accused of being "workshy" after missing the Commonwealth Day service in favour of a skiing trip with his friends which inspired a string of lurid tabloid headlines.
The Duke and Duchess are leaving their children at home for the short trip, 20 years after the death of the Duke's mother in the city.
They will visit Les Invalides, where victims and first responders from the Bataclan terror attack will share their stories.
The historic war hospital has long been working on rehabilitating those affected by the attack, with around 20 victims reported to still be in physical recovery.
The Duke and Duchess' visit has been welcomed by French press, including one magazine which noted with approval that the Royals "hadn't forgotten" the shooting.
French television news described the trip as a "charm offensive", with the Royal couple designated as Britain's "secret weapon to sweeten the bitter Brexit pill".
The visit will form part of a series of Royal tours to Europe, designed by the Foreign and Commonwealth Office as a sign of soft power even as the UK extricates itself from the European Union.
President Hollande has been among those speaking out against Brexit, warning " there must be a price" for the UK's departure.
But he will be among the first to meet the Duke and Duchess, welcoming them into the Elysee this evening. (Friday)
A Royal source said the Duke and Duchess were "incredibly honoured" that their trip has been formally recognised by the President.
The couple will then attend a reception at the British Embassy, at which they will officially launch "Les Voisins", a programme celebrating UK-French links.
Later this evening, they will attend a black tie dinner in the same venue, alongside guests chosen for careers which span the English Channel.
Among them will be Kristin Scott-Thomas who played the Queen on Broadway in Peter Morgan's play The Audience, and may offer the Duke a welcome talking point among the formalities.
Other guests will include actors Jean Reno and Audrey Tautou, Robert Pires, the footballer, several paralympians and business leaders.
The highlight of the trip for many observers will be Saturday night's Six Nations rugby match, where Wales will take on France.
The Duke has been invited in his role as patron of the Welsh Rugby Union; his first match since he took over the role from the Queen in December.
The trip is only the third time the Duke has officially visited France, following two appearances at military commemoration services.
It is the first time he has been in Paris on a public engagement since the death of his mother, Diana, Princess of Wales, nearly 20 years ago.
The Duke and Duchess will not be commemorating the anniversary in public while in Paris. The Duke's father, the Prince of Wales, visited Paris with his late first wife in 1988, with glamorous photographs of their various receptions shared around the world.
This time, all eyes will be on the Duke and Duchess and their welcome in France, as Brexit negotiations begin.
While they are there on the request of the Foreign Office, a Royal spokesman emphasised the trip was intended in the spirit of celebrating friendship across the Channel.
Later this year, they will also travel to Germany and Poland, while the Prince of Wales and Duchess of Cornwall embark on a tour of Romania, Italy, Austria and the Vatican, where they will be received by Pope Francis.