f(x) is a quintet South Korean girl group under the management of SM Entertainment since the year 2009. The chosen name was came from the mathematical notation for function which â€œfâ€ signifies for â€œflowerâ€ and the â€œxâ€ represents the femaleâ€™s double X chromosome. The group had made their debut on September 1, 2009 with their released digital single, â€œLa Cha Taâ€. The members of the group are Victoria, Amber, Luna, Sulli and Krystal.
In the late 2009, members Luna and Krystal had contributed to the soundtrack of the drama series Invincible Lee Pyung Kang with their duet, â€œHard but Easyâ€, the two had also recorded another duet song called â€œcalling out: for the KBSâ€™s drama series Cinderellaâ€™s sister. Â In the early 2010, Krystal, Luna and Amber had recorded the song, â€œSpread its Wingsâ€ for the KBSâ€™s drama series, God of Study. Later on the year 2010, Luna had released her own single, â€œBeautiful Dayâ€ as a part of the official soundtrack of another KBS drama which is â€œPlease Marry Meâ€. For KBSâ€™s drama â€œPresidentâ€ second original soundtrack, Luna and Super Juniorâ€™s Yesung had released a duet titled as â€œAnd I Love Youâ€.
Krystal had appeared on one daily Korean sitcom called â€œMore Charming By The Day” that has started from March 22, 2010 to November 2, 2010. Â The said sitcom has a total of 138 episodes but Krystal had only appeared from the 60th episode.
On April 2, 2010, Y-Star had started to air the first variety show of the group,Â Hello f(x). The program is consisted of four episodes that showed the close coverage on their preparations for their first mini-album,Â Nu ABO. On October 2, 2010, their second reality show,Â Koala, had started airing on MBC’sÂ Every1. The show was featured the group’s background life during theÂ SM Town Live ’10 World Tour.
In late 2010, Victoria, Sulli and Krystal became the model endorsers for the clothing brand,Â Calvin Klein’s X Jeans. As of music video for the song, “Beautiful Day”, it was released in December 2010 to endorse the said brand. The group had also endorsed another clothing brand,Â K-Swiss, for the 2010 Winter Collection of the said brand. Victoria was also featured in Kangta’s music video of songÂ â€œLove, Frequencyâ€
It was announced by SM Entertainment that member Amber will be coming back from USA after her long leave since June 2010 and that the group will release their studio album in the early half of the year 2011. At first it was rumored that their comeback will be on March 2011 but their member Krystal had slipped it on one TV show stating, “We f(x) are set to comeback in April.”
The first teaser photo for the said album which is entitled â€œPinocchioâ€ was released on April 7, 2011 at the groupâ€™s official website. The photo was of member Krystalâ€™s that features her orange hair. Other teaser photos have set to be revealed until April 11, 2011. The said album will be released on 20th of April, 2011.