Kim Hyo Jung (born January 11, 1991; Hangul: 김효정), better known by her stage name Hyolyn (Hangul: 효린) or often written Hyorin, is a South Korean idol singer and actress. She is best known as the leader and main vocalist of the girl group, Sistar and their sub-unit Sistar19.

In March 2011, Hyolyn was a guest on Strong Heart where she revealed that she was born prematurely and weighed in at 4.2 kg (about 9 lbs) at birth. During her mother's pregnancy, water had filled Hyolyn's stomach, which led her to become a premature birth. Bile was unable to be passed through her intestines, which eventually damaged her liver, causing a biliary atresia. Although the required surgery had low chances of sustaining life, Hyolyn was able to survive the 10-hour long surgery.

A year later, however, she was diagnosed with intussusception (a medical condition where parts of the intestine folds over into another section of the intestine) and received surgery for enterectomy.^[1]

Hyolyn auditioned for JYPE two times, and was finally accepted at the second try placing 1st place at the audition. She was set to debut in a project group with Secret's Jieun and EXID's Yuji but plans fell. ^[2] Hyolyn then left JYPE and joined Starship Entertainment, auditioning with a cover of Christina Aguilera's Hurt. ^[3]

In June 2010, Hyolyn made her debut as a member of Sistar on KBS Music Bank with their debut single, Push Push ^[4]

In early 2011, Hyolyn and group member Bora formed as a sub-group Sistar19 with the single "Ma Boy".^[5] Hyolyn had the chance to participate in the newly formed variety show "Immortal Song 2" on June. She won the first episode and received immediate attention and public love for her voice. Her new-found popularity helped spread Sistar's name tremendously to the public. Due to her great vocal ability and stage presence on the show and other variety programs, she has been labeled as the Korean Beyoncé by some singers within country.^[6][7] She participated in the show from June until September. ^[8]

On October 17, she released featured single "Ma Boy 2" with Electroboyz.^[9]

As an MBC 2012 Lunar Year special, the variety show We Got Married spin-off "Pit-a-Pat Shake" aired its pilot episode featuring virtual idol couples experiencing dating life. Hyolyn's partner was revealed to be Super Junior's Sungmin.^[10] In the pilot, Sungmin and Hyolyn performed traditional Korean opera.^[11]

Recently, Hyolyn has begun an acting career starring in the KBS drama “Dream High Season 2” as Nana, a famous idol from the fictional girl group HershE.^[12]

For Hyolyn's work with Sistar, see Sistar's discography.