"TT" is a song recorded by South Korean girl group TWICE, the lead single of their third extended play (EP) TWICEcoaster : LANE 1. The song was released on October 24, 2016 by JYP Entertainment and distributed by KT Music. It is written and composed by Sam Lewis and Black Eyed Pilseung respectively. The title "TT" refers to the emoticon used to express crying or sadness. .