TOKYO - Princess Mako, the 25-year-old eldest grandchild of Japan's Emperor Akihito and Empress Michiko, will become engaged to a university classmate and is expected to marry next year, media reports said.
The happy occasion, however, is heating up debate on the ever-shrinking royal family since Mako must become a commoner after marriage as stipulated by the Imperial House Law.
Japan's Cabinet is expected to approve a Bill on Friday to allow Akihito, 83, to step down, the first abdication by a Japanese emperor in nearly two centuries, after he said last August he feared age would make it hard to fulfil his duties, reported Reuters.
Mako's prospective fiance was identified as Kei Komuro, who lives in Yokohama and was a student at International Christian University in Tokyo, according to public broadcaster NHK.
The Imperial Household Agency later confirmed the report and said Komuro is a 25-year-old graduate student at Tokyo's Hitotsubashi University and also works at a law firm.
It will be the first engagement among the four grandchildren of Emperor Akihito. Mako is the daughter of Prince Akishino, the emperor's second son, and his wife, Kiko, reported the Japan Times.
The last marriage of a Japanese princess took place in October 2014 when Princess Noriko, the 28-year-old daughter of Emperor Akihito's late cousin Prince Takamado, tied the knot with Kunimaro Senge, the eldest son of the chief priest of Izumo Taisha, the daily said.
Princess Mako met Komuro about five years ago through a friend at International Christian University, and later accepted a marriage proposal from him, the Japan Times reported, citing an Imperial Household Agency source.
She has already introduced her boyfriend to her parents, and they have approved of the relationship, the Yomiuri Shimbun reported, citing sources.
Komuro was coy about the relationship when he appeared on Wednesday before the cameras outside the Tokyo law office where he works.
"Now is not the time for me to comment, but I want to speak at the right time," Komuro repeatedly told reporters.
Komuro, who media said once served as a "Prince of the Sea"to promote tourism in a locality near Tokyo, did say he had had a brief phone conversation with Mako in the morning before leaving for his office, telling her "I'm off".
Her response? "Have a good day."
Asked about the problem of the shortage in royals, Chief Cabinet Secretary Yoshihide Suga told a news conference on Wednesday: "There is no change in our view to proceed with consideration of steps to ensure stable imperial succession."
The legislation to allow Akihito's abdication will make no reference to the controversial topics of whether to revise a males-only succession law or to allow women to stay in the imperial family after marriage, a move conservatives fear would be a first step to letting females inherit the throne, Reuters said.
There are only four heirs to the throne - Akihito's two middle-aged sons, whose wives are in their early 50s, Akihito's octogenarian brother, and Prince Hisahito, the 10-year-old son of Akishino.
Akihito has only four grandchildren, the other three of whom are female - Mako, her younger sister, Kako, and Crown Prince Naruhito's daughter, Aiko.
The shrinking royal population - which mirrors the broader trend of Japanese society - has raised concerns that the youngest prince may also be the last.
"Under the present system, there is the risk that Hisahito will be the only one left in the imperial family," Keio University Professor Hidehiko Kasahara was quoted by media as telling an experts panel that studied the abdication issue.
Mako, who like her groom-to-be graduated from International Christian University, has a master's degree from the University of Leicester and has been working as a researcher at a museum.