This week visiting the north of the Scandinavian country, the future king and queen having been having fun as ever, turning a series of rather dry engagements on an official tour into a time to remember for them and their people.
At the Nordsoen aquarium in North Jutland, Frederik, a former naval officer, who served with the elite Royal Frogmen Corp, showed off his diving skills, while his wife of seven years looked on.
Australian-born Mary, 39, was immaculately clad in a lavender coat and floral dress that wouldn't look out of place in Kate's wardrobe.
Fred, as the 43-year-old is known to friends and family, pressed his face against the glass for a kiss, much to his other half's amusement.
And she smilingly returned the favour, blowing him a kiss, in front of the press and visitors.
Their easy rapport was also on display as they showed off their seven-month-old twins Vincent and Josephine on board the royal yacht.
The cute youngsters are the latest of four kids, they have including Christian, six, and Isabella, four.