Lee Ji-eun (Korean: 이지은; born May 16, 1993), better known by her stage name IU (Korean: 아이유), is a South Korean singer and actress. Her stage name is derived from the phrase "I and You", symbolizing that we can become one through music. Her fan club name is U-ana (Uaena), where each syllable has a different meaning: "you" is from English, "ae" is Sino-Korean for "love", and "na" is Korean for "me". In 2012, IU ranked #19 on "The 23rd Annual Independent Critics List of the 100 Most Beautiful Faces."

IU debuted on Mnet M! Countdown on September 18, 2008 with her debut single "Lost Child". It was later released as the title track for her debut mini-album Lost and Found on September 24, 2008. However, she did not gain mainstream popularity until her follow-up and debut studio album Growing Up.

On April 16, 2009, IU launched her first full album, titled Growing Up, with the lead promotional number "Boo". Within three weeks, "Boo" went up to the No.1 contenders for SBS Inkigayo, and her name also went up twice on Take 7 together with other notable artists like SG Wannabe and Younha. The song also did well on KBS Music Bank K-Chart, on Mnet M! Countdown chart, and on various online music charts.

In 2009, IU sang the ending title song, "Araro", for the acclaimed MBC drama Queen Seon Duk, where she was recommended by the director, Sam Kim, citing her "clear tone and her lyrical sensibility". She was also featured on Mighty Mouth's album Love Class in the song "희망사항". In late 2009, IU recorded MC Mong's song "Love Letter to You" featuring SHINee's Key as the rapper.