In 2001, Hisaishi produced music for another Kitano film, "Brother", and Hayao Miyazaki's animated film, "Spirited Away". The opening theme to this film, "One Summer's Day", went on to become Hisaishi's most famous composition, with over 7 million Spotify streams as of January 2021. He also served as executive producer of the Night Fantasia 4 Movement at the Japan Expo in Fukushima 2001. On October 6, Hisaishi made his debut as a film director in "Quartet", having also written both its music and script. The film received excellent reviews at the Montreal Film Festival. His first soundtrack for a foreign film, "Le Petit Poucet", was released in the same year.