Pinocchio is the first studio album and third overall physical release by South Korean girl group f(x), released on April 20, 2011 by SM Entertainment in South Korea. The album was re-released as Hot Summer (Repackage Edition) on June 14, 2011 and contained the title track "Hot Summer" as well as two singles released in 2009, "La Cha Ta" and "Chu~♡", plus the previously-released "Is It Ok?". Both versions of the album sold a total of almost 145,000 copies in South Korea.

"LA chA TA" was f(x)'s debut song, and was released digitally on September 2, 2009. Following their first live performance at the Samseong-dong Fashion Center on September 2, 2009, the music video was screened and released online the next day. The group's first broadcast performance of "La Cha Ta" was held on MBC's music show Show! Music Core on September 5, 2009. The music video for the song, released on September 2, 2009, featured the group members dancing on various theater-themed sets. They start by arriving and getting off a pink car and dancing in front of a lighted theater entrance during the night. As the song starts, members Victoria Song, Amber Liu and Sulli Choi enter the theater through the door while Luna and Krystal Jung stay behind to sing first two verses respectively. The scene shifts to individual sets. Amber, dressed as a ringmaster is on a dark stage with fire pits in front, red carpet beneath and huge hanging doors as decors at the back. Victoria, wearing a formal pink dress and jewelry, is in a room with glittering mauve-colored walls and posh pink and white hanging ornaments. Luna, wearing a golden dress, is walking up a black staircase leading to a crescent shaped shimmering golden seat. Sulli, dressed in casual form, is in a bedroom with blue walls, red carpet and a large teddy bear hanging from the wall. Krystal, dressed in formal black, is in a room with many hanging crystals and mirrors at the back. As song proceeds, girls discover that their rooms are connected and greet each other. As the song comes to an end the girls come out of the theater laughing and drive off in their car.

...
Wikipedia