f(x) (pron.: /ˌɛf ˈɛks/; Korean: 에프엑스) is a South Korean girl group formed by SM Entertainment in 2009. The quintet consists of Victoria, Amber, Luna, Sulli, and Krystal. The name is a play on the mathematical notation for function. The group made their debut on September 5, 2009 with release of the digital single “LA chA TA“. f(x) released their first EP Nu ABO in 2010 to growing popularity. f(x) released their first studio album Pinocchio in 2011. The lead single off the album “Pinocchio (Danger)” gained their first music program win and was their first song to win the triple crown.

They released their second Korean EP Electric Shock on June 10, 2012. Electric Shock reached the #1 spot on both the US and Canadian iTunes electronic albums chart soon after its release.

The lead single off their EP gained significant popularity and acclaim, domestically sweeping digital charts.


Pre-debut history

Krystal Jung was first spotted by SM Entertainment in 2000 on a family visit to Korea, which earned her a small role in a short segment of Shinhwa’s “Wedding March” music video. Sulli first debuted as a child actress in 2005 when she was selected to play young Princess Sun-hwa in the SBS television drama, The Ballad of Seo-dong.In 2006, SM Entertainment recruited Luna after seeing her performing on SBS‘s television program, “Truth Game”. Victoria was spotted by a S.M. Entertainment’s agent at a Beijing dance competition, and later joined the company. Two months later, Amber.


Other activities

Original Soundtrack

In late 2009, Luna and Krystal contributed to the soundtrack of television series Invincible Lee Pyung Kang with a duet, “Hard but Easy”.

In early 2010, Krystal, Luna and Amber also recorded the song “Spread Its Wings” for the soundtrack of the KBS‘s drama, God of Study. Krystal and Luna recorded a duet song for the KBS’s drama Cinderella’s Sister original soundtrack, called “Calling Out”.

In late 2010, Luna released a single “Beautiful Day”, as part of the official soundtrack of the KBS drama ‘Please Marry Me’. On December 23, 2010, a duet collaboration between Luna and Super Junior‘s Yesung was released, titled “And I Love You“, for the second original soundtrack of KBS’s President.

August 2012, Krystal and her older sister Jessica from Girls’ Generation released their first track together for the drama “To The Beautiful You”.

Luna and Sunny from Girls’ Generation also released a track for the drama “To the Beautiful You”.

Television and Acting careers

Krystal appeared on a daily Korean sitcom called “More Charming by the Day” which started from March 22, 2010 to November 2, 2010. The sitcom has total of 138 episodes but Krystal appeared from the 60th episode.

On April 2, 2010, Y-Star started airing first variety show of the group, Hello f(x). The program consisted of four episodes which showed close coverage on their preparations for the first mini-album, Nu ABO.

On October 2, 2010, their second reality show, Koala, started airing on MBC‘s Every1. The show featured the group’s background life during the SMTown Live ’10 World Tour.

From May 2010, F(x) members started to appear in variety show on regular basis. Victoria was cast in We Got Married to become a couple with Nichkhun from 2PM. They were a couple for a little over a year and were the only couple to have crossed seasons. She was also cast as regular member of Invincible Youth, and appeared in the show until it ended in December 2010. Luna appeared in Star King and became regular member of the show. She went on to win “New Star” (신인상) award in 2010 SBS Entertainment Award (2010 연예대상). Sulli was cast as the co-host of Inkigayo (인기가요) along with Jo Kwon from 2AM and Jung Yong Hwa of C.N.Blue. She is still hosting the show with Jo Kwon, along with new co-hosts IU and Lee Gi Kwang

In late 2010, members Victoria, Sulli and Krystal became model endorsers for the clothing brand, Calvin Klein‘s X Jeans. A music video for the song, “Beautiful Day”, was released in December 2010 to endorse the brand. The group also endorsed another clothing brand, K-Swiss, for their 2010 winter collection.

In addition to those endorsements, Victoria also was featured in Kangta’s music video of his song 爱,频率 (“Love,Frequency”/”Breaka Shaka”).

From May 2011 through August 2011, Krystal appeared as a contestant on Kim Yuna‘s celebrity ice skating show, “Kim Yuna’s Kiss and Cry.” After consistently scoring near the top of the competition, Krystal and her partner Lee Don Hun won the show with their flawless performance of “Carmen.”Krystal and Lee Don Hun were later invited to participate in “Kim Yuna’s Ice Show—All That Skate Summer 2011” on August 14 and 15.

Towards the end of the year, f(x) members pursued individual acting activities. On September 19, 2011, MBC aired the first episode of “High Kick 3,” a daily sitcom show in which Krystal starred as one of the lead roles. In October, Amber was cast as a member of the second season of Invincible Youth.[31] In November, Victoria starred alongside Super Junior’s Kyuhyun in TRAX’s music video for the song “Blind”. In December, CSTV began airing the weekend drama “Saving Mrs. Go Bong Shil“, which features Luna in the role of Seo In Young.

On December 31, Victoria together with her We Got Married partner Nichkhun from 2PM MC-ed the 2011 MBC Gayo Dajaejun Festival.

In January 2012, Victoria starting filming When Love Walked In a Taiwanese drama.

On August 15, Korean drama To the Beautiful You started airing, featuring Sulli and SHINee’s Minho.


In June 2010, Amber rapped in Korean and English for Taiwanese Mandopop artist Danson Tang on track, “I’m Back” from his third album The First Second.


Main article: f(x) discography

Korean discography

Studio albums
Repackaged albums

Japanese discography



Main article: F(x) videography

On May 2, 2011, SM Entertainment created an Official Channel on YouTube for f(x).

Music videos

Year Title Length Notes
“LA chA TA” 3:26 Debut Single
“Chocolate Love” (electro-pop version) 3:49 Commercial film for the LG’s Chocolate.
“Chu” (stylized as “Chu~♡”) 3:18
“Lollipop” 3:14 Commercial film for LG’s Lollipop.
“Thrill Love” 2:57 OST for the drama of Hungry Romeo, Luxury Juliet.
“Nu ABO” 3:49
“Beautiful Day” 1:22 Commercial film for Calvin Klein‘s X Jeans.
2011 “Pinocchio (Danger)” 3:13
“Hot Summer” 3:46
2012 “Electric Shock” 3:18
“Hot Summer” (Japanese Ver.) 3:58



Supporting act


Music Programs

These are a collection of f(x) wins on Korea’s televised music shows. Inkigayo is aired on SBS, M! Countdown on Korean cable channel, Music Bank on KBS and Show Champion on MBC Music.

Music Bank

Year Date Song
2011 April 29 “Pinocchio (Danger)”
May 20
2012 June 22 “Electric Shock”
June 29

M! Countdown

Year Date Song
2011 May 5 “Pinocchio (Danger)”
May 12
May 19
June 30 “Hot Summer”
2012 June 21 “Electric Shock”
June 28
July 5


Year Date Song
2011 May 8 “Pinocchio (Danger)”
May 15
May 22
June 26 “Hot Summer”
2012 July 1 “Electric Shock”
July 8

Show Champion

Year Date Song
2012 June 26 “Electric Shock”
July 3

Other Media

On June 1, 2011, S.M. Entertainment, together with NEOWIZ Internet Corporation, Ltd, released an iPhone application which features f(x)’s album, Pinocchio. The app can be downloaded for free on iTunes. and f(x)’s First Mini Album “NU ABO” for iPhone/iPod Touch. The app can be purchased for US$4.99 on iTunes.

Also,released Android applications in android market[39] Live Wallpaper & Widget app, “Hot Summer” for US$2.80 on android market.

On December 31, 2011, as part of Global KakaoTalk Plus Friend, SMTown artists opened accounts on KakaoTalk, available on iOS, Android, and BlackBerry OS.

On March 19, 2012. S.M,Ltd. released 2012 f(x) Diary app for iOS.


  • NU ABO by Neowiz Internet
  • Pinocchio / Hot Summer by Neowiz Internet
  • 2012 f(x) Diary by S.M,Ltd.


  • f(x) PINOCCHIO(Danger) Live Wallpaper & Widget
  • f(x) Hot Summer M/V Theme with live wallpaper
  • f(x) Pinocchio by Neowiz Internet
  • f(x) Hot Summer [Repackage] by Neowiz Internet
  • f(x) Theme Shop by dlto
  • 2012 f(x) diary by S.M. Entertainment


Further information: F(x) filmography


Year Title Notes Role
2012 I AM. Documentary of SMTown Live ’11 World Tour in New York As themselves

Television series

Year Title Notes
2010 YStar Hello f(x)
2010–2011 MBC f(x)’s Koala Amber didn’t participate in the series due to an ankle injury.
2010 – present SBS “Star King” members are recurring in the show