Lee debuted as a male model under her birth name Dae-hak, becoming known for her feminine appearance and wearing women's clothing on the catwalk, but ultimately wished to pursue a career as an actor.
She appeared in the films My Boss, My Hero (2001) and Sex Is Zero (2002), providing comic relief in effeminate male roles, but felt pressured into cutting her hair and building up muscle.
Lee recalled that, "once I entered showbiz, I was forced to live a life I didn't like", and growing increasingly unhappy, made several attempts at suicide before deciding to become a woman.
Adopting the given name Si-yeon, Lee underwent sex reassignment surgery in 2007, and admitted to having doubts over her sexuality since being in secondary school.
