My grandfather was a well known musician, widely known as the best string bass player in Australia for many years. Of course he wasn't all that well known outside of the music industry, but as a kid I did see him on TV sometimes.
I'm not actually related to Tom Jones. He's just a guy who, I have it on good authority, was almost as good at shagging as I am.
My grandfather-in-law was an actual king, but not a blood relative of mine so it doesn't really count.