Yeo Jin-goo (Korean: 여진구; Hanja: 呂珍九) is a South Korean actor. Yeo began his career as a child actor, debuting in the film Sad Movie (2005). Nicknamed "Nation's Little Brother", he went on to play the younger characters of the lead roles in movies and television dramas such as in A Frozen Flower (2008), Giant (2010), Moon Embracing the Sun (2012), and Missing You (2012). He is known for playing the title character in the action thriller Hwayi: A Monster Boy (2013), for which he won Best New Actor at the Blue Dragon Film Awards. Since then, he has taken on lead roles in the films Shoot Me in the Heart (2015), The Long Way Home (2015), and Warriors of the Dawn (2017). He has also starred in the dramas Orange Marmalade (2015), The Royal Gambler (2016), Circle (2017), Reunited Worlds (2017), The Crowned Clown (2019), My Absolute Boyfriend (2019), Hotel Del Luna (2019), and Beyond Evil(2021).