I'm guessing the voice is extremely effected and that it purposefully doesn't sound like Christina (which would make sense no? Why would they want to give it away so easily). Also she must have some sort of face mask on so obviously the cheek structure and general face don't look like hers.
I do hope that the instrumentals are indicative of the sound for her new album though. That would just be...
yeah that's why when her stylist was ranting off about iamami not being her on twitter , i wasnt even too sure about taking her word since she could have easily not been told .