Jeong Yun-o, known professionally as Jaehyun, is a South Korean singer. He is a member of the South Korean boy band NCT and its sub-units NCT 127 and NCT DoJaeJung. He made his solo debut on August 26, 2024, with the studio album J.
First introduced in December 2013 as a trainee under the pre-debut team SM Rookies, he debuted in April 2016 as a member of the rotational unit NCT U and as a member of Seoul-based fixed unit NCT 127 in July 2016. He later joined the fixed unit NCT DoJaeJung in April 2023.
As of 2024, Jaehyun has released five solo singles: "Forever Only" and "Horizon", both as part of the NCT Lab project, while "Roses", "Dandelion", and "Smoke" as part of his debut album J. Apart from music, he has also hosted the radio show NCT Night Night from March 2017 to January 2019 and the television program Inkigayo from October 2019 to February 2021. He later debuted as an actor with a leading role in the college romance television series Dear. M, and he is set to make his feature film debut in the mystery thriller film You Will Die In 6 Hours.