Kim Se Jeong is a South Korean singer, dancer, actress, and former member of I.O.I (아이오아이) and GUGUDAN (구구단). She graduated from Indeogwon High School and later obtained an associate's degree in Practical Music from Hanyang Women's University.

In January 2016, she participated in the survival show "Produce 101", where she finished in 2nd place, thus securing a spot in the show's project group.

She debuted in May 2016 as I.O.I's main vocalist with their first EP, "Chrysalis", and actively promoted as a whole group and as separate sub-units for less than a year before YMC Entertainment (YMC엔터테인먼트) and Swing Entertainment (스윙엔터테인먼트) announced their disbandment in January 2017.

Around the same time, she debuted in June 2016 as GUGUDAN's main vocalist, center and face of the group with their first mini-album, "Act 1. The Little Mermaid". After some initial success, the group began struggling to find promotional activities, and new releases were not as frequent. Jellyfish Entertainment (젤리피쉬엔터테인먼트) decided to put the full group on hiatus.

She made her debut as a solo artist in November 2016 with the single "Flower Road". And, in July 2017, she made her acting debut with the lead role in the KBS2 drama "School 2017".

In June 2018, she joined a newly created sub-unit called GUGUDAN SEMINA (구구단 세미나) and released their first self-titled single album. This sub-unit was created to hide the fact that the full group remained on a prolonged hiatus.

In December 2020, after two years of no activity, Jellyfish announced that GUGUDAN had officially disbanded. She decided to continue her acting career while occasionally providing an OST for a drama or collaborating with another artist.

On March 24, 2026, she signed an exclusive contract with BH Entertainment (비에이치엔터테인먼트).

(Source: kisskh) Edit Biography