Mark who plays Special Agent Leroy Jethro Gibbs slaps Michael's character, Special Agent Anthony "Tony" DiNozzo, on the back of his head. That moment was improvised and was received so positively ...

NCIS: Origins gave insight into the man who killed Leroy Jethro Gibbs' wife and child ... Mark Harmon's iconic Michael Weatherly slap happened during an improvised NCIS scene NCIS episode ...