Is Alicia Keys' No Makeup Rule Causing A Feud With Miley Cyrus On The Voice??

Is a good ol' fashioned celebrity feud about to pop off on The Voice?!
Rumors are swirling that Alicia Keys and Miley Cyrus aren't getting along so well when the cameras aren't rolling -- and the newcomer judges apparently have a makeup issue to thank?? What the what?!
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According to Radar Online, sources at The Voice are worried things could blow up very quickly between Miley and Alicia, and it all stems from the latter's decision to