GRAND BLUE is the digital single by HYNN. It was released on Agust 10, 2023. HYNN (흰) is a South Korean singer-songwriter under BOD Entertainment and New Order Entertainment. She is best known for making to the top 3 on Superstar K 2016. She is also a member of the female project groups WSG Wannabe and The Listen. She made her solo debut on December 28, 2018 with the digital single “Let Me Out”.