Crown Prince Naruhito and Crown Princess Masako arrived in Tonga on Friday to attend the coronation of the South Pacific island nation's new king, on what is the princess's first overseas trip since 2013.

The Crown Princess, who has been receiving treatment for a stress-induced illness for more than a decade, showed no trace of fatigue from the nearly 10-hour flight as she stepped off the plane and shook hands with Crown Prince Tupouto'a Ulukalala.

Also in line to welcome the royal couple were Japanese residents of Tonga. When a 4-year-old local girl gave her a bouquet, Crown Princess Masako greeted her cheek to cheek.

The Japanese royal couple will attend the coronation of King Tupou VI at a church in the capital Nukualofa on Saturday and a luncheon hosted at the Royal Palace afterward. They are scheduled to return home on Monday.

The Crown Princess, who was diagnosed in 2004 as having an adjustment disorder, will skip other events involving her husband in consideration of her condition, according to the Imperial Household Agency.

Crown Princess Masako last made an overseas trip in 2013 to attend the coronation in the Netherlands of King Willem-Alexander, her first official overseas trip in 11 years. She has since engaged in more official duties than before.