GUESS WHICH R&B STAR IS GOING TO BE THE NEW JUDGE ON SIMON COWELL'S X-FACTOR!!!

Def Jam head LA Reid would be hosting Simon Cowell's new reallity show American Idol.
Well now GUESS WHO has just OFFICIALLY been chosen as his THE OTHER Co-Host . . . . MARIAH CAREY.
The announcement should come this week.

MC doesn't need to do this....