'The Voice's' Blake Shelton Says 'X Factor' Rival Simon Cowell is 'Always Mouthing Off'

Lewis Jacobs/NBC

Blake Shelton wishes Simon Cowell would put up or shut up.

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'The X Factor's' Simon Cowell Says He is 'Pissed Off' at 'The Voice'

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Cowell hasn't made his feelings secret about NBC's choice to pit The Voice against Fox's The X Factor, telling reporters last week that the showdown constituted a violation of a "gentleman's agreement" and he was "pissed off" about it.

Asked how he feels about Cowell's comments, the country star and Voice coach tells Access Hollywood, "He's been doing it since [The Voice] came on the air."

"Every time I turn around the guy is mouthing off," an exasperated Shelton says. "Don't y'all wish you had time to bitch and moan like that? It's like, 'Do you own show! Come on! Put something together there and do you thing.'" 

Shelton adds, "We'll just do ours and we won't mouth off about you. I wish I had that much time. The guy must just have more free time than he knows what to do with."

In the end, it will be the viewers who decide who comes out on top in this battle of these musical mentors. X Factor's much-hooplah'd second season debut airs tonight on Fox, while The Voice's third season debuted on NBC on Monday to softer-than-season-2 numbers.