Britney NOT the singer on Scream & Shout?

Last night rapper, actress, designer and living legend EVE claimed the singer on Scream & Shout is NOT Britney Spears, saying: "I heard that might not be Britney....I heard [it might be someone else in the studio] but you know I don't know, it could be Britney...but I heard it wasn't."

(click image for video since it's US only sry)