Mr Komuro proposed to Princess Mako after dinner one evening in December 2013.
Mako and Komuro, both 25, expressed great joy over the engagement and Emperor Akihito's approval, during a press conference held at Akasaka Palace in Tokyo, Efe news reported. However, at the request of her parents Prince Akishino and Princess Kiko, who supported Princess Mako's relationship with Komuro, the bodyguards tried to keep a distance from the couple by blending into the crowd.
Princess Mako, a granddaughter of the emperor and empress, expressed delight with her engagement to her fiance, Kei Komuro, as the young couple exchanged smiles at a news conference in Tokyo on September 3.
The Imperial Household Agency first said there were plans underway for the couple's engagement.
"First I was attracted by his bright smile", Princess Mako said of her fiancee during a press conference. "I was aware since my childhood that I'll leave a royal status once I marry", she said, adding that she felt "really happy" with her engagement.
The 26-year-old princess will marry a commoner named Kei Komuro.
However, Princess Mako left Japan in August 2012 to study in Britain, while Komuro went to the United States to study in autumn of the same year. The announcement was originally scheduled for July, but the couple made a decision to postpone it in light of the torrential downpours in northern Kyushu earlier that month. Princess Mako is the first of the Imperial House's four grandchildren to get engaged.
Their engagement will become official in Imperial terms after Komuro's messenger visited the princess' Imperial residence with gifts. The wedding is expected to take place next year, according to the public broadcaster NHK.
In 2016, 83-year-old Emperor Akihito announced publicly that poor health following heart surgery and prostate cancer had made him unfit to properly fulfill his duties as emperor of the country. The Imperial family will witness the first wedding since 2014.
Mako is a part-time researcher at the University of Tokyo's University Museum.
Referring to the princess's achievement in fostering momentum for the Japanese tennis circle, Watanabe said, "It's regrettable that she leaves the imperial household at this time, but I wish her happiness for many years to come".