As the Euro2016 Battle of Britain between the Welsh side and neighbours England looms near, Leicester City's King says it is not the wisest to get stuck into Three Lions striker Vardy who scored 24 goals in the Premier League last season.
"You have seen the way he plays, he is an aggressive sort of player," said King.
"Sometimes, in our own changing room at Leicester, we try and get into him because we know if he is firing on all cylinders then you know you have a good chance of winning the game.
"But you have to be careful with him as an opponent. If you get under his skin too much he can make you pay for that. I just hope he doesn't score against us.
"Of course there are ways of stopping him. I know more than most about how you can try and stop him.
"I am not saying it is going to work, he has had an unbelievable season and won many personal awards which he fully deserves, but we are confident and think we can cause an upset."
The Group B encounter comes with an enormous amount of intrigue as Wales sit top of the standings on three points as 'big brothers' England are third with the point they recorded from Saturday's disappointing 1-1 draw with Russia.