You wouldn’t be the one liable. Any company that hired you might be liable if you sound like a famous voice and the more famous individual had already declined using their voice.

The company would also be liable if they used your voice and claimed it was someone more famous.

Ultimately you’re not liable for having a similar voice because you’re not trying to fool people you’re someone else. It’s the company that hired you who’s doing that.

This is why tribute acts and impressionists are fine…as long as they are clear they’re not the original artist