Princess Mako, a niece of Emperor Naruhito and the eldest daughter of Crown Prince Akishino, turned 28 on Wednesday.

The princess has engaged in some official duties previously performed by Crown Prince Akishino and Crown Princess Kiko since May 1 when her father became heir to the throne with the enthronement of his brother Emperor Naruhito.

As for her previously announced engagement to Kei Komuro, her longtime boyfriend from university days, the Imperial Household Agency said in February last year that the couple will delay the event until 2020, citing a "lack of preparation time."

The decision followed a string of reports that Komuro's mother was involved in a financial dispute with her former fiance over education expenses for her son that her former partner shouldered, among other things.

Among Princess Mako's recent official duties, she visited Peru and Bolivia in July to mark the 120th anniversary of the start of Japanese immigration to South America.

She also attended a ceremony at the national urban greenery fair in Nagano Prefecture in May and the closing ceremony of the national athletic meet in Ibaraki Prefecture in October — the type of duties previously performed by her parents.

On Tuesday, she attended the enthronement ceremony of Emperor Naruhito with her parents, her younger sister Kako and others.