The time for legal advice is before you retained the actor's serivces for the project.
Eveything should have been spelled out in a legally bindng agreement, inlcuding the fact that you have total editorial control over the project.
The fact that he agreed to work for free should have no bearing on this.
This is your project, not his!
Next time have it spelled out in a legal agreement prepared by a lawyer and signed by both parties.
This experience can go down as a lesson learned.

Hey Tony, how did this situation turn out by the way?
Did the actor come to his senses after you talked to him?