For the occasion, the Queen consort wore a floor-sweeping golden embellished gown teamed with a matching hat.
Dazzling earrings, a clutch bag and a blue and yellow sash completed her regal look for her first Prince's Day as Queen.
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Meanwhile, King Willem-Alexander was handsome in striped trousers and a morning coat for one of the biggest events on the royal calendar.
Tuesday was especially important one for the recently inaugurated King as he opened the new parliamentary year with the King's Speech for the first time.
Dressed in all their finery, the royal couple arrived at Ridderzaal – or Knight's Hall – in true royal style in a golden horse-drawn carriage for the official opening of the country's parliament.
With beaming smiles and enthusiastic waves for the thousands of supporters who turned out to cheer them, the King and Queen later greeted the crowds of well-wishers from the balcony of Palace Noordeinde in the Hague, the Netherlands.
They were accompanied by Willem's younger brother Prince Constantijn and his wife Princess Laurentien.
The Dutch celebration comes a month after the funeral of Willem's other brother Prince Johan Friso.
The younger brother of King Willem-Alexander tragically died aged 44 on 12 August after being in a coma for almost a year and a half following a skiing accident in Lech, Austria.
The highly private funeral, attended by around 80 people, saw the Dutch royals unified for the sombre occasion, with the adults dressed in black and children in white.