Heo Ga-yoon is a South Korean actress and singer, best known for being a member of the girl group 4Minute and its sub-group 2Yoon. She was born on May 18, 1990, in Goyang, South Korea. She started her journey in the entertainment industry by placing second in SM's 9th "Best Singer Contest" in 2005. In 2009, Heo Gayoon made her official debut as a member of 4Minute with their hit single "Hot Issue." The group quickly gained popularity, and Heo Gayoon participated in various solo and group activities associated with the band. In 2010, she contributed to the soundtrack for The Woman Who Still Wants to Marry and collaborated with Sunny Side on tracks like "Bad Guy Good Girl." Heo Gayoon continued to expand her career with soundtrack contributions such as "Wind Blow" for My Princess and "Shameless Lie" for Lie to Me. In 2011, she made her acting debut with a cameo in I'm a Flower Too and released "I Think It Was a Dream" for the drama Poseidon. In 2014, Heo Gayoon co-hosted the fashion program Style Log and released "Nightmare" for the drama Yong-pal. She made her film debut in 2016 with Father, Daughter. Following the disbandment of 4Minute in June 2016, Heo Gayoon transitioned to acting, joining BS Company as an actress. She has since appeared in films like Daughter Me (2016), The Drug King (2018), and Search Out (2020), as well as television series such as Light and Shadow (2012) and Let's Eat 2 (2015).