On September 17, 2015, it was revealed that Sung-kyu would star in a new KBS series, Youth Express, alongside comedian Kim Sook and actor Park Jaemin.
Pada tanggal 17 September 2015, terungkap bahwa Sung-kyu akan membintangi serial KBS baru, Youth Express, bersama komedian Kim Sook dan aktor Park Jaemin.