TOKYO - The announcement of Japanese Emperor Akihito's eldest granddaughter's imminent wedding to a university friend was reported prominently by the country's media Wednesday.

Public broadcaster NHK reported Tuesday evening that Princess Mako is likely to marry her university classmate Kei Komuro in 2018.

In a ten-minute chat with the media on Wednesday, 25-year-old Komuro said he had spoken to Mako over the telephone in the morning and added that he would give out more details at the appropriate time.

The engagement will become official with an exchange of ceremonial gifts after which a date will be set for the wedding.

The couple had met five years ago at an event at a restaurant in Tokyo, a source from the Imperial Household told NHK.

The source added that Komuro proposed to the 25-year-old princess about a year after they met and that Mako's parents have already approved of the relationship.

The princess is working as a researcher at a museum in Tokyo while Komuro, a resident of the Yokohama locality, is a legal assistant at a law office, and is also pursuing a master's in business law.

Mako is the elder daughter of Prince Akishino, the second son of the emperor and second in line to the Chrysanthemum Throne after Prince Naruhito.

Mako's marriage will further shrink Japan's imperial family, an aged and dwindling institution, which is heading towards a huge generational gap.

The marriage could also reopen the debate on the law that has been governing the royal household since 1947, and that doesn't recognize the so-called collateral institutional branches, making women who marry out of royalty to lose their royal status.

The world's oldest reigning hereditary dynasty comprises 19 members, out of which only four are men, making them the only ones who can accede to the throne: Emperor Akihito (83), Prince Naruhito (57), Prince Akishino (51) and Prince Hisahito (10), younger brother of Princess Mako.