Cristiano Ronaldo Jacks Reporter's Mic ... Throws It In Lake

Cristiano Ronaldo might be the newest Splash Bro ... 'cause he just Deep 6'd a reporter's microphone into a lake -- and it was all captured on video.

The soccer superstar was out in France when a reporter came up to him, put the mic in his face and asked if he was prepared for the big Portugal vs. Hungary match later in the day.

Ronaldo casually snatched the mic and lobbed it over his shoulder ... sending it to a watery grave.

The reporter spoke with BBC after the incident and said, "I'm not sure why he did it. I think it was a momentary thing. I think he would not have done it if he had thought about it."

"We are a TV channel of a major newspaper in Portugal. We produce a lot of news about him. Some of it he doesn't like. Perhaps that's why he did it."

The reporter says he hasn't gotten an apology from Ronaldo -- but says they're scheduled to fly back to Portugal on the same plane.