On landing for a ten-day state visit, the royals headed for his former family home in the Phan Dinh Phung district.
French-born Henrik looked delighted to wander around his old house, telling anecdotes and pointing out his favourite spots like the gardens and the pagoda.
He spent the first five years of his life until 1939 in what was then French Indochina, returning to the capital Hanoi in 1950 to complete secondary school in the local French lycée.
Several generations of the prince’s family lived in the Asian country tending to business interests, including rice and coffee plantations and a newspaper.
They left in 1954 because of the deteriorating security situation.
For his wife Queen Margarethe and son Frederik it was moving to return with the 75-year-old to the country where he spent some of the happiest years of his life.
A particularly poignant moment came when they accompanied him to St Joseph's Cathedral to remember the life of his grandfather Henri de Laborde de Monpezat.
Watched by his nearest and dearest, Henrik bowed his head for a few minutes after unveiling a plaque in honor of his grandfather, whose grave disappeared during the war.