I recall a Star Trek episode where Kirk et al visited an alien world (populated by humans) which was run by fascists. The popular leader had died a while back. The boys in the back room were horrified at the possible backlash from the public with the leaders death.

So they put the body in a freezer. Every once in a while, they stood it up in front of a TV camera and attached some puppet strings to make arms move. The mike was place right in front of the leader's mouth, so no one could see lips not moving as the leader spoke. The public never suspected.

This just might come true! There's a lot more technology out there since this Star Trek epidode aired.