On the whole, of course it doesn't make you an ignorant person. But certainly you'd admit that you're ignorant of who he is and what he does. In fact, that's what you just said.
It doesn't bother me that you don't know who he is, although he's definitely pretty famous. And that's why I said it would be something you would just google and not comment on.
I'd say that being innocently ignorant and being called ignorant are two different things.