Secret Number's Lea admitted that in the past she went back to Japan because of her decreasing health.

"It was when I was about 20 years old, my health was so bad at the time, things were bad at the time so I ended going back to Japan. I thought: I want to live here as it is - to be honest, I thought so because Japan is my home country. The head of the company came to visit me in Japan. He always said come with me, come with me... so I came back to Korea but before that, I had a big argument with my mom. I went to the airport alone. I had a really bad fight with my mom because my health was so bad at the time, my mother is a nurse so she worried about me. I wanted to debut soon and show mom a good side of me. I'm still trying!"

Lea first debuted in 2013 when she joined group SKarf, but then in 2014 group suddenly disbanded. In 2016 she was part of a trainee group with Weki Meki's Suyeon, then in 2017 she appeared in MIXNINE. FInally she re-debuted as member of Secret Number in 2020.