 Now, KC and JoJo have other famous singing cousins as well. Take, for instance, Dave Hollister, who once sang lead vocals for the R&B group Blackstreet. And then the first cousin to KC and JoJo is Fantasia. That's a lot of vocal power in that family and a hell of a R&B family tree. I'm Bill Black, and that's another Bet You Didn't Know Music fact on the Black Information Network.