There're quite a few singers who seem to transcend both genres. You can easily find Bessie Smith in either Jazz or Blues... and I think the same can be said for Billie Holiday?
Cher Lloyd transcends no less than seventeen genres*.
*said genres, in order: Shit. Shit. Shit.
Actually kinda catchy shit. Shit! Shit? Aw shit. Fuck. Fuck this shit. No, really, fuck. Fuck me. Shitshitshitmakeitstopmakeitstop. There is no God. Oh noooooooooooooooooooooooooooooo! There are four lights! ..... and bleh.
I am gifting this to an audience of unsuspecting fools the next time I run tech at the local comedy club.