Yoon Se Eun (윤세은; or simply Seeun) is a South Korean singer and former child actress currently under High Up Entertainment. She is a member of the girl group STAYC and former member of the pre-debut group Play M Girls. Prior to her idol training, she was a child actress under Kiana Entertainment with credits on dramas such as Circle and The Guardians.
Seeun was revealed as the third member of STAYC on September 9, 2020. She made her debut on November 12, 2020 with the release of the group's first single album "Star To A Young Culture".