Park Yong-kyu, better known by the stage name Park Seo-joon (박서준), is a South Korean actor. He is best known for his starring roles in the television series Kill Me, Heal Me (2015), She Was Pretty (2015), Hwarang: The Poet Warrior Youth (2016–2017), Fight for My Way (2017), What's Wrong with Secretary Kim (2018), Itaewon Class (2020) and Gyeongseong Creature (2023–2024). He has also appeared in films such as The Chronicles of Evil (2015), Midnight Runners (2017), The Divine Fury (2019), Concrete Utopia (2023), and The Marvels (2023).

Hwarang: The Poet Warrior Youth is a 2016 South Korean television series starring Park Seo-joon, Go Ara and Park Hyung-sik. It revolves around an elite group of young men called Hwarang, who discover their passion, friendship and love in the turmoil of the Silla Kingdom. The series aired every Monday and Tuesday at 22:00 (KST) on KBS2, from December 19, 2016 to February 21, 2017.