Chrystal Soo Jung, professionally known as Krystal, is an American singer and actress based in South Korea. She debuted in 2009 as a member of South Korean girl group f(x) and has further participated in SM Entertainment’s project group SM The Ballad.
Amber Josephine Liu, known professionally as Amber or Amber Liu, is a Taiwanese American singer, rapper, songwriter and composer based in South Korea. She is a member of the South Korean girl group f(x). She debuted as a solo artist in February 2015 with the release of her EP, Beautiful.