"This is a cynical, cold-hearted, unprofessional way of doing business," Cowell told TMZ. "These guys have really got it in for us. It's nothing short of dirty tricks."
Cowell added that he was under the impression the two networks had a "gentleman's agreement" where The Voice would air on Mondays and Tuesdays and X Factor on Wednesdays and Thursdays. This week, NBC announced that a third night of The Voice will air on Wednesday, Sept. 12 at 8/7c, the same time that X Factor will premiere. Cowell says the schedule shift was made out of fear.
"The reason they've done this is they don't want people to see X Factor because they've heard how good the series is," he said. "They don't want their audience to see Britney Spears. They don't want their audience to see Demi Lovato."
Finally, Cowell added: "Britney is not going to appreciate the fact that Christina [Aguilera]-- who has been a bit of a rival -- isn't allowing Britney to have a night of her own. She's going to be devastated because she's put her heart and soul into this."