L.A Reid, Demi Lovato, Simon cowell, britney spears Britney Spears and Demi Lovato are joining the judging panel on "The X Factor" this fall, part of Fox's effort to boost its underperforming music competition shows. The network's executives, in presenting next season's schedule to advertisers on Monday, also promised changes for "American Idol. "I'm so excited about the whole experience ," Spears said. " It's going to be so much fun and different from anything I've ever done. I'm ready to find the true star" . They replace judges Paula Abdul and Nicole Scherzinger, who were dispatched along with host Steve Jones after last fall's debut season of the competition didn't meet the creator's inflated expectations.