Jeon Hee-jin (Korean: 전희진; born October 19, 2000), known mononymously as HeeJin (희진) is a South Korean singer under MODHAUS. She is the first revealed member of girl group LOONA (Hangul: 이달의 소녀) , and is a member of its first sub-unit, LOOΠΔ 1/3. She is currently a member of girl group ARTMS. She debuted as a LOONA member on October 5, 2016 with the solo single album HeeJin. On October 31, 2023, she made her official solo debut with her first mini album , featuring the title track "Algorithm".