Little Mermaid Approach (hi, I turned out to have more internet here than I thought). David Mitchell trades his voice to one of the more eccentric sea witches out there in exchange for getting to be a beautiful lady and romance Charlie Brooker. She makes him a beautiful lady who looks remarkably like a younger David Mitchell in a dress. Charlie Brooker falls for this mysterious mute woman (he does the sensible thing and gets her a pen and paper for communication, and possibly one of those electronic voice things you type into as time goes by). Sea-witch-induced complications ensue. And they all live happily ever after (unless you decide to use the original Hans Christian Anderson ending).