Miller v. Ford Motor Co. would disagree. There is a viable legal precedent, and it is very arguably illegal.
> The appellate court ruled that the voice of someone famous as a singer is distinctive to their person and image and therefore, as a part of their identity, it is unlawful to imitate their voice without express consent and approval. The appellate court reversed the district court's decision and ruled in favor of Midler, indicating her voice was protected against unauthorized use.
They’d have to prove the voice actor was imitating SJ. If OpenAI recorded the entire interview process as well as the sessions where they recorded the actor for samples to steer the model with then it should be open and shut. There’s also the fact of the 4 other voices. Who are they meant to be?
> The appellate court ruled that the voice of someone famous as a singer is distinctive to their person and image and therefore, as a part of their identity, it is unlawful to imitate their voice without express consent and approval. The appellate court reversed the district court's decision and ruled in favor of Midler, indicating her voice was protected against unauthorized use.
https://en.m.wikipedia.org/wiki/Midler_v._Ford_Motor_Co.