Actor Gabriel "G-Rod" Rodriguez confronted Machine Gun Kelly in an Atlanta restaurant last night for his notorious Tweet about Eminem's daughter Hailie -- which led to all the beef between Em and MGK.

I'm gonna say it because it has to be said, you're a pussy for going for family," he told to MGK's face.

According to Rodriguez, who's a father of three, he had a brief confrontation with MGK over that, and then the manager of the restaurant kicked him out.

Later, five MGK goons caught Rodriguez at the hotel and beat him down in the lobby. You can hear Rodriguez speak about the incident below.

Police have surveillance video on the beating and are investigating. They confirmed MGK wasn't involved in the actual beatdown. Rodriguez had to go to the ER for facial injuries.