WATCH: Arnold Schwarzenegger gets drop-kicked from behind!

Arnold Schwarzenegger got drop-kicked from behind as he posed for a selfie with fans.

The 71-year-old bodybuilder was completely surprised as he was knocked into the crowd during the attack. He thought he'd been pushed about by over-eager fans.

He was hosting the Arnold Classic Africa in South Africa and seemed in good spirits as he posed for pics and signed autographs. All of a sudden a man leaps in the air and kicks him in the back.

Security rushed in and a man was quickly apprehended.

Arnold later tweeted: "Thanks for your concerns, but there is nothing to worry about. I thought I was just jostled by the crowd, which happens a lot. "I only realized I was kicked when I saw the video like all of you. I’m just glad the idiot didn’t interrupt my Snapchat."