'Nice Guy' Song Joong Ki fell in love with picking on his best friend Lee Kwang Soo.

Today, the KBS2 drama "Nice Guy" website posted a making video.

The video was when Park Jae Gil (Lee Kwang Soo) and Kang Maru (Song Joong Ki) were filming for episode 16, when Jae Gil is trying to convince Maru to get a surgery.

While filming, silly Song Joong Ki said to the director, "Doesn't Kwang Soo's outfit make him look old?", and Lee Kwang Soo, looking at his outfit, asked his coordinator, "We have another jacket, right?"

Song Joong Ki, smiling, said "You're so gullible. Have some confidence", but Lee Kwang Soo said, "It's okay. Bring me the jacket", and Song Joong Ki kept cracking up.

So Lee Kwang Soo decided to change both his pants and his jacket. But Lee Kwang Soo changed in front of all other staff members, shocking everyone. Song Joong Ki, who couldn't let this go, held the camera and went to film Lee Kwang Soo changing. He proudly said, "I filmed this."

Photo Credit: KBS