Denmark's King Fredrick and Queen Mary celebrate 20 years together

It’s been 20 years since King Frederik stood in front of the Copenhagen Cathedral congregation and vowed to love and protect his queen, Mary.

The couple, who are on a state visit to Norway, marked their wedding anniversary with a gala dinner at the Norway Royal house, hosted by their close friends, King Harald V and Queen Sonja of Norway, as well as Crown Prince Haakon and Crown Princess Mette-Marit.

“Dear Mary, you took on a big task when you went and fell in love with this sporty Dane,” said Harald, Europe's oldest reigning monarch, in his speech at the dinner.

King Harald honoured the couple in his speech. (PHOTO: Gallo Images/Getty Images)

“You gave up a lot that was safe and familiar, you made Denmark and the Danes your own heartland, I know that you have also been a great support for our beloved Queen Margrethe,” he added.

The kings of Norway and Sweden are both cousins of the former Danish queen Margrethe II, Frederik's mother.

The Norwegian and Danish royal families dined at the Banqueting Hall of the Norway royal house. (PHOTO: Gallo Images/Getty Images)

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Queen Mary previously revealed that she was unaware that Fredrik was royalty when they first met at The Slip Inn pub in Sydney during the 2000 Olympics.

A source close to them previously revealed that they instantly clicked the first day they met. (PHOTO: Gallo Images/Getty Images)

“The first time we met we shook hands,” she recalled. “I didn't know he was the prince of Denmark.”

Someone told her shortly after their encounter that she'd just met the Crown Prince of Denmark.

The pair maintained a long-distance relationship until she moved to Denmark to study at Copenhagen's Studieskolen in 2001. Two years later they announced their engagement.

The couple on their wedding day. (PHOTO: Gallo Images/Getty Images)

They tied the knot in 2004 and the then Prince Frederik tearfully exchanged vows with Mary.

“From today, Mary is mine and I am hers,” he said. “I love her and I will protect her with all my love.”

The Danish royals with their children (from left) Prince Christian, Princess Isabella, and their twins, Prince Vincent and Princess Josephine. (PHOTO: Gallo Images/Getty Images)

A year after their wedding they welcomed their first child, Prince Christian (18). Their eldest daughter, Princess Isabella was born in 2007, and twins Prince Vincent and Princess Josephine followed in 2011.

Frederik was crowned king and Mary queen consort, in January this year, after the surprise abdication of his mother, Queen Margrethe II. 

SOURCES: HELLOMAGAZINE.COM, DAILYMAIL.CO.UK, VOGUE.COM.AU