Longguo & Shihyun (Hangul: 용국 & 시현) is a South Korean duo formed by Choon Entertainment in Seoul, South Korea. The duo previously participated in Produce 101 Season 2. They debuted on July 31, 2017, with the single "the.the.the". Longguo was a member of fan-made project boy group JBJ, having signed a seven-month contract with the label Fave Entertainment.