Do it amazing DIA! Hello, I'm Huihyeon!
Ki Hui-hyun (기희현) better known by the mononym Huihyeon and former stage name Cathy, is a South Korean singer. She is best known as a member of South Korean girl group DIA. She was a competitor in Produce 101.
On September 14, 2015, Huihyeon debuted as a member of DIA with the release of the group's first studio album Do It Amazing.
In 2016, she, alongside fellow member Chaeyeon, became a contestant on the survival show Produce 101. She was eliminated in episode 11 after ranking 19th place.
In 2016, she also appeared on Mnet's rap survival program Unpretty Rapstar 3 as a contestant.