Shannon Arrum Williams, known mononymously as Shannon, is a British streamer and former singer. In South Korea, she is known for being a contestant of K-pop Star 6: The Last Chance. Prior to debut, Shannon has released two single: "Day and Night" with T-ara's Areum and Gavy NJ's Gun-ji in September 2012 and then "Remember You" featuring SPEED's Jungkook in January 2014 before making her official debuted in December 2014 with digital single "Daybreak Rain". Since her debut, she has released two extended plays, six singles and three soundtrack appearances. In 2016, Shannon also made her debut as an actress with cast in drama Moorim School: Saga of the Brave.

Amber Josephine Liu, 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.