Yoo Yeon-jung (; born August 3, 1999), known mononymously as Yeonjung, is a South Korean singer signed under Starship Entertainment and Yuehua Entertainment. She is best known for being a member of the South Korean-Chinese girl group WJSN, and for finishing 11th in the survival show Produce 101, making her a member of I.O.I. Early life and education Yoo was born on August 3, 1999, in Gwangmyeong, Gyeonggi Province, South Korea. In 2017, Yoo was accepted through rolling admission into the musical theatre program of the Performance & Film Department at Dankook University. Career 2016: Produce 101 and I.O.I Yoo, together with Kim Tae-ha and Shim Chae-eun represented Starship Entertainment in the Mnet reality-survival program Produce 101, which aimed to form an eleven-member girl group that would promote for a year under YMC Entertainment. Yoo placed 11th with a total of 136,780 votes in the final episode and debuted as a member of I.O.I. On May 4, project girl group I.O.I debuted with the mini-album Chrysalis. 2016–present: WJSN, V-1 and solo activities While still an active member of I.O.I, Yoo was introduced as the thirteenth member of WJSN on July 11. Yoo made her official debut with WJSN on August 17, 2016. They released their second mini album The Secret with all 13 members. Yoo collaborated with Yoo Seung-woo on the track "I Will Be On Your Side" which was released on November 10, 2016. Yoo, together with bandmate Dawon, released the track "Fire & Ice" as part of The Snow Queen 3: Fire and Ice OST. The track was released on December 16, 2016. On May 31, 2017, Yoo released the soundtrack "You're Dazzling" for the television series Queen for Seven Days. Yoo collaborated with Brother Su and participated in the soundtrack of Love Playlist 2 with the track "Toy". She was featured in DinDin's "#Drive". "Meloholic" was released for the OCN drama Meloholic. She then collaborated with Maktub on the single "Marry You". Yoo released two soundtracks for television series in 2018, "Your Name Is..." and "Stay With You" for The Undateables and Where Stars Land respectively. "Tell Me, Please" was released as the second part of the soundtrack of Melting Me Softly on October 14, 2019. Yoo also made her acting debut, making a cameo in A Korean Odyssey. In September 2019, Yoo participated in the survival program show, V-1, to select the Vocal Queen among the