Behind the fancy stage performances idol groups put on in front of thousands of their fans, there are the efforts of the stars that were built through years and years of practice. The top idol groups Big Bang's G-Dragon, EXO's Suho, and ZEST's Shun are similar in that they are the leaders of their team and have spent one of the longest time as a trainee before their debut.

1. Big Bang G-Dragon (trainee period 11 years)

Big Bang's fashion icon G-Dragon won first place at a dance competition at a ski resort when he was 8 and spent 5 years as a trainee in SM Entertainment. After that, he entered YG Entertainment and spent 6 long years once again as a trainee and finally debuted as a part of Big Bang.

2. EXO Suho (trainee period 7 years)

EXO's leader Suho spent 7 long years as a trainee. He started in 2005 and debuted with the song "MAMA" in 2012 and he saw many trainees give up throughout his period. He saw Taemin and Jonghyun debut as SHINee before him but now he became the leader of the rising group EXO.

3. ZEST Shun (trainee period 7 years)

The new group ZEST's leader Shun also spent 7 years as a trainee. At the debut showcase held last month, he said, "It's been 7 years since I decided that I want to be a singer. In that time period I went to the army and I even worked as a staff member for other groups' showcases," tearing up. ZEST is also catching much attention as soon as they made their debut.