I think your age is such that it's not unexpected of you to have never heard of R. Kelly, but how on Earth could you have missed Freddy [sic] Mercury?
I didn't miss him, I just didn't know who the front man for Queen was. Not on my list of priorities.
Now Jefferson Airplane > Starship with Grace Slick ... that's my jam. Ditto for Big Brother and the Holding Company with Janis.
As for R. Kelly, a number of my e-correspondents have chimed in to advise that he's famous for being famous. (But at least I've heard of the Kardashians.) Quite frankly, R. Kelly would seem to be a waste of space and carbon, essentially the human equivalent of a cheap ink-jet printer.