Lee Ji-eun, also known by her stage name IU (아이유), is a South Korean singer-songwriter and actress. She signed with LOEN Entertainment in 2007 as a trainee and debuted as a singer at the age of fifteen with the EP Lost and Found (2008). Although her follow-up albums brought mainstream success, it was only after the release of "Good Day", 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 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.