볼빨간사춘기 (Bolbbalgan4/BOL4) is a South Korean folk act under Shofar Music formed in 2016. Bolbbalgan4 was originally composed of two former participants of Superstar K6, a South Korean television talent show: 안지영 (Ahn Ji-young) and 우지윤 (Woo Ji-yoon). On April 2, 2020, Shofar Music announced that Ji-yoon had left the duo due to personal concerns about her future career but Ji-young would continue to promote as Bolbbalgan4.