The 83-year-old queen, who took over the throne in 1972, is the longest-serving monarch in Europe following the death of Queen Elizabeth II in September 2022.
Archive photos show the young princess, then 31, stood at the balcony at Christiansborg Palace - just like her son did today - as the then-Prime Minister Jens Otto Krag proclaimed her monarch.
The man who would be king whose son is about to fulfil his dreams of a throne royalcentral.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from royalcentral.co.uk Daily Mail and Mail on Sunday newspapers.