Noriko Kamachi (蒲池 法子, Kamachi Noriko, born 10 March 1962), professionally known as Seiko Matsuda (松田 聖子, Matsuda Seiko), is a Japanese pop singer and songwriter, known for being one of the most popular Japanese idols of the 1980s. Since then, she is still actively releasing new singles and albums, doing annual summer concert tours, winter dinner shows, high-profile TV commercials and movies, and makes frequent TV appearances and radio broadcasts.

Due to her popularity in the 1980s and her long career, she has been dubbed the “Eternal Idol” by the Japanese media. In January 2011, the Japanese music television program Music Station listed her as the 2nd best-selling idol of all time in Japan, with 29,510,000 records sold. She placed right behind pop group SMAP and ahead of Akina Nakamori, her biggest rival from the 1980s, who was listed in third place. In 2016, however, Ian Martin of The Japan Times compared her output unfavorably with that of Hikaru Utada, describing Matsuda as “first and foremost an idol rather than an artist. Her legacy is best expressed in singles rather than albums.”