The US Courts have been struggling with this seemingly non-sensical question in a unusual and unfortunate fact situation.
The plaintiff is an actress who made a brief appearance in a low-budget film entitled "Desert Warrior". The film was never released. However, her scene later appeared in an anti-Islamic film released on Youtube entitled "Innocence of Muslims". Her brief performance had been partially dubbed over with words that seemed to ask "Is your Mohammed a child molester?". The latter film attracted public protests, worldwide news coverage and death threats against the plaintiff. She asked Google to remove the video from YouTube. When it refused, she sought relief from the courts for copyright infringment.
In particular, the plaintiff claimed that she owned copyright in her performance and that she never expressly transferred title in that copyright to the film producer. However, the US Copyright Office refused her application to register copyright in her performance and the trial court found that the film producer had an implied license to use her performance in his film. Her request for an injunction was denied.
On appeal, the trial court decision was reversed and a limited injunction was granted on the grounds that a film is the joint work to which all parties intend to contribute and, in that context, the producer enjoyed only a limited license to use the plaintiff's performance for the purposes of creating the original film. In fundamentally changing the character of the film and her performance, the producer voided the intentions of the parties to create a joint work and exceeded the limited of his implied license.
Finally, on May 18, 2015, a further appeal restored the trial court decision and quashed the injunction. In its decision, the court concluded the copyright protected "work" in question was a film and not the plaintiff's brief performance. It found that recognizing individual actors as having a potential copyright claim in their performances would splinter a film into multiple "works" and turn copyright for the film into Swiss Cheese. As a practical consideration, the court pointed out that untangling the chain of title to dozens or even hundreds of independent copyright protected works could tie film production into knots.
The interesting point for Canada is that, unlike the US, we do recognize actors (and other performers) as enjoying copyright in their performances. Unlike the US, Canada also recognizes that performers enjoy "moral rights" in their performance and these rights may restrict how the film producer may ultimately use their performance. Nevertheless, our film industry manages to cope.
Bob Tarantino of Denton's has an excellent blog article here that explores the differences between Canadian and US copyright law on this issue and explains how we manage to cope.