THE HAGUE - The Netherlands' Willem-Alexander becomes Europe's youngest monarch Tuesday when Queen Beatrix abdicates and his country hails the avowedly 21st-century king with a massive orange-hued party.
Willem-Alexander will be the first Dutch king since 1890 and the first of a new wave of European monarchs, whose ageing blue blood -- average age 71 -- is increasingly watered down.
Amsterdam's population is set to double with at least 800,000 visitors flooding the city's streets and canals as Beatrix ends her 33-year reign by signing the act of abdication at the royal palace.
While Beatrix was known for her formal court, Willem-Alexander has already said that he and his glamorous Argentine-born queen consort Maxima will not be "protocol fetishists".
Parliament last year stripped his mother of her last remaining role in forming governments, and the new king has said he would accept a purely ceremonial role should parliament so decide.
The Dutch monarch's current political role is restricted to signing laws and meeting regularly with the prime minister.
The king will be sworn in rather than crowned at the deconsecrated Nieuwe Kerk, a stone's throw from the palace, before a joint session of the houses of parliament.
A cornucopia of concerts and club nights has been organised around the city, including an open-air set by world-famous Dutch DJ Armin van Buuren, and orange-themed street parties are planned across the nation.
Maxima is largely responsible for having made her husband popular after an allegedly boozy youth which earned him the nickname "Prince Pils".
The ever-smiling Maxima has mastered the Dutch language and even took a charity swim in Amsterdam's canals, endearing herself further in a country that expects their royals to be at once normal and regal.
Willem-Alexander's brother Friso will also be missed, in a coma following a skiing accident in Austria in February 2012.
Speaking ahead of the enthronement, Willem-Alexander said that "people can address me as they wish because then they can feel comfortable".
He stressed he wanted to "be a king that can bring society together, representative and encouraging in the 21st century".
Willem-Alexander and Maxima's three daughters, including future queen Catharina-Amalia will be at their parents' side during the day.
When Beatrix in January announced she would abdicate, Catharina-Amalia asked her father how long he would do the job of king.
"Wouldn't you like to know," he answered.