Queen Beatrix of the Netherlands abdicated on Tuesday, handing over to her eldest son Willem-Alexander who is the first King of the Netherlands since 1890.
The 75-year-old signed the instrument of abdication in Amsterdam after 33 years on the throne following in the tradition of her mother and grandmother. She will now take the title of Princess.
Huge crowds of orange-clad partygoers are in Amsterdam to pay tribute to the popular queen, who announced her intention to stand down in January this year, saying her son was ready to reign and that it was time for the throne to be held by "a new generation", the BBC reports.
Beatrix formally relinquished throne at a short ceremony in the Royal Palace, signing a statement which read: "I now withdraw from my office of Queen of the Netherlands, and the monarchy will now be transferred to my eldest son, Willem-Alexander."
There were huge cheers from the crowds outside, watching on giant screens in Dam Square, as she and the prince and his wife, Maxima, signed the deed. Shortly after, the trio emerged on a balcony above Dam Square.
King Willem-Alexander, 47, thanked his mother for "33 moving and interesting years", saying he and the Dutch public and people in Dutch overseas territories were "intensely grateful" to her.
The trio held hands on the balcony as the national anthem was played, before the new king and queen's three young daughters were brought out to wave at the crowds.
Willem-Alexander will later be officially sworn at the Nieuwe Kerk, before a joint session of the Dutch parliament. Maxima, a 41-year-old Argentine-born investment banker, will become queen consort.
On Tuesday evening the royal family will take part in a water pageant. The ceremonies will be attended by other invited royals and high-ranking dignitaries, including Britain's Prince Charles and the Duchess of Cornwall, Prince Felipe and Princess Letizia of Spain and Denmark's Crown Prince Frederik and his wife Mary.
On Monday, Queen Beatrix thanked the nation in a televised address, saying the people's devotion had given her the strength to carry on during reign. Paying tribute to her husband Prince Claus, who died in 2002, she said he had helped modernise the House of Orange.
King Willem-Alexander is the seventh monarch from the House of Orange-Nassau, which has ruled the Netherlands since the early 19th Century. Under Dutch law, the monarch has few powers and the role is considered ceremonial.
Nearly one million people are expected to take part in the street party in Amsterdam dressed in orange - the royal colour. Demonstrators who oppose the monarchy intend to dress in white.