Object Movement with Horizontal Camera Rotation

I have a sphere with a VR camera inside it. The camera rotates vertically and horizontally (360 degrees). Inside the sphere there is an object. I would like this object to move with the horizontal rotation of the camera.

So for example, if there is an object close to the bottom of the sphere, if the camera rotates to the right, the play button will move with the camera's rotation so that it will still be in front of the camera.

I am using Google's Cardboard Head script.

Any ideas?