Hyun-Jin Ryu sings on a new K-pop song, and you need to listen to it by Matt Monagan | MLB.com Cut4 No, yeah. We're serious. Courtesy of @allkpop (thank you, @allkpop), here's Ryu singing the chorus on "Smile Again" -- a charitable tune with Korean pop groups Trouble Maker and G. NA: Amazing song. Amazing video. Amazing Ryu. Smile again, and again, and again.