Jubilant crowds celebrated the transition, a rare event in a nation where royal succession typically occurs due to a monarch's death.

Denmark's monarchy, dating back to the 10th century, serves a largely ceremonial role today. The change of power took place in Christiansborg Palace, the historic seat of Danish authority, encompassing government and royal functions.

Prime Minister Mette Frederiksen announced Frederik's new title from the palace balcony, with King Frederik, in full military regalia, by her side, later joined by his family, including his Australian-born wife, now Queen Mary, and their children. The national anthem played as the public displayed their support.

King Frederik expressed his aim to be a unifying figure for Denmark, emphasizing a commitment to his country. The royal couple then greeted the crowd from Amalienborg, their residence, enjoying a warm public reception.

Queen Margrethe signed her abdication at a grand ceremony, entrusting the throne to Frederik, who will now reign beside Queen Mary, while their eldest son becomes Crown Prince Christian. Despite the queen's recent health challenges prompting her resignation, she retains her royal title.

The historic event, highlighted by personal touches like the new king's heart-touching gesture and Queen Mary's elegant attire, captivated locals and international visitors, including Australians celebrating one of their own ascending to royalty.

Surveys indicate a strong public belief in the new king and queen's readiness for their roles, reflecting the enduring popularity of Denmark's royal institution despite being a constitutional monarchy in a society that values egalitarianism.