Ng Sze Kai (born Wu Si Jia), also known as Shin, is a singer from Guangzhou, China. She has one-quarter Korean ancestry. In 2012, she debuted in Hong Kong as a member of girl group As One (AS1). The group later debuted in South Korea in 2015. Her popularity rose in South Korea after competing in Produce 101. Since 2017, she left As One and shifted her career focus to mainland China.