Yes, I know, they recorded this video with a potato. Though this dance practice video is very old, their dance performance is excellent way beyond their age.
f(x) or some have nicknamed them as "function girls", is a South Korean girl group formed by SM Entertainment. The group made their debut on September 5, 2009 with release of a digital single "La Cha Ta". The quintet consists of Victoria, Amber, Luna, Sulli, and Krystal.