JOO recently came back into the music scene with her new mini-album, "Heartmade", but fans have been wondering why it had taken her so long to return. The singer had originally debuted back in 2008 with "Because of a Man", and although she received a lot of love at the time, she made a difficult decision that drew a lot of respect from Park Jin Young. On the afternoon of January 5th, Park Jin Young tweeted, "JOO's new song, 'Bad Guy,' has just been released. Actually, she believed that her skills were inadequate for a debut, and voluntarily returned to life as a trainee for two years... It's really difficult to do that.. What a lovely little kid." Fine-tuning her skills to a level where she felt satisfied, she finally made her comeback this week. Fans were delighted with her return, and Park Jin Young concluded his series of tweets with, "Fighting!" If you haven't heard her sophisticated sound yet, check it out through here. Source: Star News via Daum Photo: JYP Entertainment