Lee Hye-ri, better known mononymously as Hyeri, is a South Korean actress, singer, and television personality. She rose to fame as the youngest member of girl group Girl's Day, and was named as the "Nation's Little Sister" by the South Korean media due to her immense popularity after appearing as a fixed cast member on Real Men (2014).

Girl's Day (Korean: 걸스데이) is a South Korean girl group formed by Dream T Entertainment in 2010. The group consists of members Sojin, Minah, Yura, and Hyeri. Members Jisun and Jiin officially left the group in 2010, while Jihae left in late 2012.