Lee Ji-eun (Korean: 이지은; born May 16, 1993), known professionally as IU (Korean: 아이유), is a South Korean singer-songwriter and actress. The name IU is a combination of 'I' and 'you' meaning "you and I become one through music." She signed with Kakao M (formerly LOEN Entertainment, now Kakao Entertainment) in 2007 as a trainee and debuted as a singer at the age of fifteen with her first mini album Lost and Found (2008). Although her follow-up albums, Growing Up and IU...IM, brought mainstream success, it was after the release of "Good Day" (Korean: 좋은 날), the lead single from her 2010 album Real, that she achieved national stardom. "Good Day" went on to spend five consecutive weeks at the top position of South Korea's Gaon Digital Chart, and in 2019, it was ranked number one on Billboard's "100 Greatest K-Pop Songs of the 2010s" list.
With the success of her 2011 albums, Real+ and Last Fantasy, IU established herself as a formidable force on the music charts of her native country and further cemented her girl next door image as Korea's "little sister". She is known now as "The Nation's Sweetheart". 2011 also saw her first foray into songwriting with "Hold My Hand", which was written for the television series The Greatest Love. IU's third full-length album release, Modern Times (2013), showcased a more mature style that marked a departure from her earlier girlish image, with several tracks reaching the top 10 positions on Gaon Digital Chart. The album was ranked number two on Billboard's "25 Greatest K-Pop Albums of the 2010s" list. While her subsequent releases, including albums A Flower Bookmark (2014), Chat-Shire (2015), Palette (2017) and Lilac (2021) continued to deviate from mainstream K-pop styles, IU retained her dominance on music charts. Chat-Shire marked the first time she is credited as the sole lyricist and composer of her own album.
IU has released a total of five studio albums and nine extended plays in her career, scoring three number-one albums and twenty-six number-one singles on the Gaon Music Charts. One of the best-selling solo acts in the group-dominated K-pop industry, she has been included on Forbes magazine's annual Korea Power Celebrity list since 2012 and reached a peak ranking of number three that year. Billboard recognized IU as the all-time leader of its Korea K-pop Hot 100 chart with the most number-one songs and the artist who has held the number-one position for the most weeks. She was named Gallup Korea's Singer of the Year in 2014 and in 2017.
Aside from her music career, IU has ventured into hosting radio and television shows, as well as acting. Following her supporting role in teen drama Dream High and minor appearances in several television series, she starred in You're the Best, Lee Soon-shin, Pretty Man, The Producers, Moon Lovers: Scarlet Heart Ryeo, My Mister, Persona, and Hotel Del Luna.