But there's nothing wrong with this! Let's say I'm making a movie. I have an old wizard character similar to Gandolf in Lord of the Rings, so I contact the guy

But there's nothing wrong with this! Let's say I'm making a movie. I have an old wizard character similar to Gandolf in Lord of the Rings, so I contact the guy who played Gandolf in Lord of the Rings. He says no, so I hire a different actor who also fits the "old wise wizard" archetype. Is any of that illegal?