Frederik is the heir apparent to the throne, which means that should Frederik succeed, she will automatically become Queen of Denmark.
The couple met at the Slip Inn, a pub in Sydney when the prince was visiting Australia during the 2000 Summer Olympics.
Their official engagement in 2003 and their marriage the following year was the subject of extensive attention from Australian and European news media, which portrayed the marriage as a modern "fairytale" romance between a prince and a commoner.