On May 18, 2016, Amuro released her third independent maxi-single "Mint", which was used as the theme song of Fuji TV series "Bokuno Yabai Tsuma" (2016). Despite reaching number four on the region's single chart, the digital sales skyrocketed with the music video of the song, and achieved platinum status months later. The same year in June, Amuro accepted an offer by NHK to record the theme song for the Japanese broadcast of 2016 Summer Olympics and Paralympics in Rio de Janeiro. The single was titled "Hero" and saw a rise in its physical sales, achieving a gold certification by RIAJ. On October 26, 2016, Amuro released two songs "Dear Diary" and "Fighter" as a double A-side single "Dear Diary/Fighter". Both songs were used in "", a 2016 movie adaption of the manga of the same name.