Hey Girl is a group of Taiwanese singers. Channel [V] held an audition for the show Wo Ai Hei Se Hui (我愛黑澀會), a variety show that aims to create new female entertainers in Taiwan. At the end of 2005, Channel [V] picked nine members to represent the other girls. These nine members were Gui Gui, Xiao Jie, Mei Mei, Apple, Xiao Xun, Ya Tou, Xiao Man, Tong Tong, and Da Ya. Together, they are affectionately known as the Qiu Niu Niu (Chinese: 九妞妞; pinyin: Jiǔ Niū Niū) for short.

The nine members were separated into two groups for their third EP release: Da Ya, Xiao Man, Ya Tou, Gui Gui, and Apple comprised Fen Hong Gao Ya Dian (Traditional Chinese: 粉紅高壓電; pinyin: Fěn Hóng Gāo Yā Diàn; literally: "high-voltage pink"), and Mei Mei, Xiao Xun, Xiao Jie, and Tong Tong (since departed) comprised Tian Xin Hong Zha Ji (Traditional Chinese: 甜心轟炸機; pinyin: Tián Xīn Hōng Zhà Jī; literally: "sweet-hearted flying bombers").

Source: Wikipedia