Yoo Jeong-yeon (유정연; born November 1, 1996), known mononymously as Jeongyeon (정연), is a South Korean singer. She is a member and the lead vocalist of the girl group TWICE, where she debuted on October 20, 2015, with the mini album The Story Begins. On November 1, 2023, Jeongyeon released a cover of O Christmas Tree, as part of Apple Music's Carols Covered playlist, which was then released on all other music platforms on February 1, 2024.