Choi was born in Vancouver, Canada. She moved with her family to Hong Kong a few years later. She is fluent in Cantonese and Mandarin. Charlene Choi was educated at a number of institutions. After graduating from Rosaryhill School, where many other pop stars had attended, she started working full-time as a model in Hong Kong. She was scouted by Emperor Entertainment Group, and was then linked with Gillian Chung to form the C-pop duo Twins.