'Strong Heart 2' Kim Bum Soo, "I've had a Singing Battle with Lena Park Before"

Vocalist Kim Bum Soo revealed that he has had a singing ad-lib battle with Lena Park before.

Today on SBS "Strong Heart 2," the two vocalists appeared as guests.

Kim Bum Soo stated, "I had a concert last year with her. We prepared long and hard for this as our fans were anticipating a great performance. We decided to have a singing ad-lib battle. Both of us are not really competitive so it didn't matte who won, but after hearing the crowd's response to her, I started getting a bit nervous. We were supposed to go up slowly, but I ended up starting out too high and so she started getting competitive too."

Along with this story, the two also revealed stories about their past as well.