Amber Josephine Liu (born September 18, 1992), also known mononymously as Amber, is an American singer, rapper, and songwriter. She debuted as a member of the South Korean girl group f(x) in September 2009. In 2015, she became the first f(x) member to make a solo debut with the release of her first extended play Beautiful and has since released solo singles in Korean, English, and Mandarin. In July 2018, she joined Steel Wool Entertainment following her original label SM Entertainment’s joint partnership with Steel Wool to manage her American activities. In September 2019, she left SM and exclusively signed with Steel Wool prior to the release of her 2020 extended play X. In May 2021, she also signed with Ryce Entertainment for her activities in China following a successful stint as a mentor in survival show Produce Camp 2021.