Though he's had enormous success as an actor, Seo In Guk has always been a singer. He first came to the attention of the public in 2009 at age 21 as the inaugural winner of competition show Superstar K, and immediately found a place on the charts with his husky voice and sweet R&B-inspired tunes. His acting career then took off, with a charismatic leading role in the wildly popular drama Reply 1997, but he's continued to make music, both sentimental soundtrack ballads and upbeat acoustic pop.