Prince William and Kate Middleton's St Patrick's Day outing – all the photos

The Duke and Duchess of Cambridge stepped out on Sunday to mark St Patrick's Day. The royal couple travelled to Hounslow, west London, to visit the 1st Battalion Irish Guards at their base. As always, William and Kate will take part in the traditional proceedings, and watch 350 soldiers participate in the parade, with William taking the salute.

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Following on from this, Kate will then hand out shamrocks to officers and warrant officers. This is a tradition that was started back in 1901 by Queen Alexandra, the wife of Edward VII. After the parade, William and Kate will go on to enjoy a lunch with the officers, and with tradition, fans can expect to see the pair sip on some Guinness.

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As ever, all eyes will be on Kate's outfit. Keeping with tradition, the royal is set to turn heads in a green ensemble. Each year, the Duchess also wears a rather special accessory - the Cartier shamrock brooch which is historically loaned to royal family members for engagements with the Guards. Previously it has been worn by the Queen Mother and Princess Anne. This is an engagement that William and Kate have been doing for the past few years, although in 2016, Kate didn’t make the outing, instead choosing to spend time with her young family. Keep updated throughout the event…

Kate stepped out dressed in a stunning green coat and co-ordinating fascinator, which was teamed with her Gianvito Rossi pumps. 

The St Patrick's Day parade concludes with a march-past where Prince William will take the salute.

The Duchess of Cambridge was in great spirits at the St Patrick's Day parade at Cavalry Barracks in Hounslow. This time last year, Kate was pregnant with Prince Louis, opting to drink water rather than Guinness during the event. 

Kate was on hand, as with tradition, to hand out shamrocks to officers and warrant officers at the St Patrick's Day parade. 

Alongside its role serving in British conflicts overseas, the Irish Guards also serve in ceremonial and public duties at Buckingham Palace, Windsor Castle, St James's Palace and the Tower of London.

Kate was reunited with her furry friend Domhnall, an Irish wolfhound and mascot she has met several times previously.

Kate beamed as she petted Irish wolfhound Domhnall. The Duchess is a big fan of animals, and is the owner of cocker spaniel Lupo.

Kate was all smiles as she passed around the shamrocks.

William and Kate looked in great spirits as they joined in the St Patrick's Day celebrations on Sunday.

Kate chose to wear a custom green Alexander McQueen coat to visit the 1st Battalion Irish Guards at their base alongside husband Prince William. She teamed it with a co-ordinating clutch and Gianvito Rossi's 'Piper' suede pumps, and wore her hair up in a stylish chignon.

Kate was given a beautiful bouquet of flowers from the officers at the St Patrick's Day parade.

Kate enjoyed sipping a pint of Guinness this year, shutting down any rumours that she's expecting another baby.