Frozen camera following player

I might be being stupid here but I'm trying to create a camera that attaches to a 3rd person controller that follows the player in a frozen position. Say the camera starts at a set position behind the controller, no matter which direction the controller moves the camera stays in the start position but just moves to follow the controller. Can someone just point me in the right direction. In simple terms it only moves on the X and Y axis dependant on which way the controller moves. I know this is a dead simple question however I'm having a brain fart...