Ever wondered what happens behind the scenes of a No. 1 hit?

The latest Agent Kim Reactivated clip shows So Ji Sub and Joo Sang Wook mastering intense wire stunts. But the real show-stealers?

Choi Dae Hoon and Yoon Kyung Ho! Their hilarious, unscripted ad-libs left the cast in stitches, proving that true action chemistry thrives on pure, chaotic fun.