Princess Ayako, the youngest daughter of Emperor Akihito's late cousin, is set to marry commoner Kei Moriya on Monday, relinquishing her royal status.
She wore a Heian-era style hairdo, which is swept back into a ponytail, and a traditional robe splashed with red and green patterns, while Mr Moriya wore coattails.
The bride changed her kimono for a traditional red kouchiki with wide sleeves.
Princess Ayako said at a press conference held in July after an official announcement of their upcoming engagement that she hit it off with Moriya from the beginning and enjoyed talking with him so much that she did not feel like it was their first meeting.
Women who marry commoners must leave the family..
When the couple announced their engagement this summer, the Imperial House Economy Council (which Prime Minister Shinzo Abe sits on) convened and made a decision to give Princess Ayako a lump-sum payment of about $US950,000 so that she could keep up her high standard of living after leaving the family, The Japan Times reported.
"I'm very happy that many people were able to celebrate (our marriage)", the princess told reporters following the ceremony.
But if you were thinking that (no longer) Princess Ayako and her new hubby are going to end up scrimping and saving to get by, you'd be completely wrong - although she won't benefit from the royal allowance any more, she will get a lump sum of $950,000 (106.75 million yen/£740,000) from the Japanese government for living expenses.
Her mother said in a statement she had raised her daughter to "prepare for the day when she supports herself" and wishes that the two "will build a good family full of joy and happiness".
"I'm delighted at this happy occasion", he said.
Ayako's mother and Moriya's had been long-time friends. She will become Ayako Moriya after signing marriage papers later Monday. The country's much-loved Emperor Akihitio announced that he will abdicate on April 30, 2019, passing the Chrysanthemum Throne to his son Crown Prince Naruhito.