NHK has learned Japan's government and the Imperial Household Agency are making arrangements for Crown Prince and Princess Akishino to attend the coronation ceremony for Britain's King Charles III in May.
Sources say Britain has sent an invitation to the May 6 event at Westminster Abbey in London.
Japan's Imperial family and the British royal family have been close.
In 1953, Emperor Emeritus Akihito, then the crown prince, attended the coronation ceremony of Queen Elizabeth II on behalf of his father.
Emperor Naruhito and Empress Masako took part in the Queen's state funeral last September.