Japanese Crown Prince Fumihito and his wife Princess Kiko will make an official visit to Vietnam in late September on the occasion of the 50th anniversary of diplomatic relations between the two countries, the Imperial Household Agency said Wednesday.

The goodwill visit is expected to last for around a week, with arrangements being made for the couple to participate in official events related to the Japan-Vietnam diplomatic milestone, the agency said.

A formal invitation was issued by Vietnam in early August, it said. The couple last made an official visit there in 1999, alongside trips to Laos and Thailand.

The upcoming journey will mark the third official visit abroad by the couple since the May 2019 ascension of Emperor Naruhito, which made Crown Prince Fumihito -- the emperor's younger brother -- next in line to the throne.

Composite photo shows Crown Prince Fumihito (L) and his wife Crown Princess Kiko. (Kyodo)

The crown prince and his wife previously visited Poland and Finland in 2019 to commemorate the centennial of diplomatic ties with the two countries, and Britain in May this year to attend the coronation of King Charles III.