Seo Hye-lin, better known by her stage name Hyelin, is a South Korean singer and member of the girl group EXID. Born on August 23, 1993 in Gwangju, South Korea, Hyelin had always dreamed of becoming a singer since she was young. Hyelin joined Superstar K3 in 2011 but failed to advance in the competition. Hyelin officially became a member of EXID in April 2012, alongside Solji. Before joining EXID, Hyelin had auditioned and trained with the group's original company but was cut from the lineup before their debut. However, after the departure of Yuji, Dami, and Haeryung, she was added to the lineup for her vocals and dancing skills, along with Solji, creating the current five-member group. In 2016, EXID released their first full album, Street, which featured Hyelin's long-awaited duo with Jeonghwa in the track "Are You Hungry?". Due to Solji's thyroid condition, Hyelin had to take over main vocalist responsibilities in EXID's songs and performances. EXID made their first promotions without Solji with the title track "Night Rather Than Day" from their third mini-album Eclipse (2017). In November of the same year, they released the mini-album Full Moon, which featured Hyelin's solo track "Foolish," her first solo work since joining EXID. She made her solo debut on May 6, 2021, with the digital single "Lonely." On January 15, 2022, it was confirmed that Hyelin had not renewed her contract with Banana Culture and had signed with sidusHQ.