The Imperial Household Agency said Tuesday it will officially announce the engagement of Princess Nori -- the 35-year-old daughter of Emperor Akihito and Empress Michiko -- to Tokyo Metropolitan Government employee Yoshiki Kuroda on Dec. 18.

The announcement will be made by agency head Toshio Yuasa and followed by a news conference by the couple the same day, the agency said, adding that the time and other details will be decided later.

The engagement was a secret until the Asahi Shimbun broke the story in early November, prompting the agency to accelerate its announcement.

The agency earlier said an official announcement would be made in late December in line with the wishes of Princess Nori and the 39-year-old bureaucrat.