With a sound that pulls from R&B, jazz, rock, and retro pop, Kim Do Hoon follows one philosophy when making music: Let's have fun. That earnest, lighthearted approach has yielded some major (and majorly catchy) K-pop hits, like Junggigo & Soyou's winsome duet “Some,” MAMAMOO's ‘90s R&B throwback “Um Oh Ah Yeh,” and IU's sticky-sweet “Marshmallow.”