Yoo Chan-wook (Korean: 유찬욱; born April 27, 2000), known professionally as Be'O (Korean: 비오; stylized in all caps), is a South Korean rapper and songwriter. He first garnered attention when he appeared on the rap competition TV show Show Me the Money 10 in 2021. Be'O signed to hip hop record label FameUs Entertainment in 2020 where he released the single albums Monster (2020) and Bipolar (2021). In 2021, he released the single "Counting Stars", which peaked at number one on the Gaon Digital Chart.