Singer Seo In Guk is back with a new single and he wants to "Shake It Up" with you on today's episode of KBS's 'Music Bank'. "Shake It Up" is the work of American composer Drew Ryan Scott, who's already worked with countless other Korean singers, including Brian Joo. Producer Hwang Se Jin, who's known for his stunning arrangements of Jang Hye Jin's songs on MBC's 'I Am a Singer', also contributed as the project's head director. With such a strong foundation of support, Seo In Guk's "Shake It Up" will surely be the summer theme song for many years to come. Check out his fun comeback stage below!