It pays to have a superstar singer as one of your best friend. BTS’ Kim Tae-hyung has written and produced a song called “Sweet Night” for Park Seo-joon’s hit K-drama, “Itaewon Class.” The tune will — of course — be sung by Kim, also known to fans as V. The title is a nod to Dan Bam, the name of the pub that Park’s character owns. In Korean, Dan Bam translates into … you guessed it … sweet night.