Seconded. It's like at a few parts of the song it sounds like it could be Ke$ha, but it might as well be Pixie Lott's voice autotuned a little bit or altered in another way. It's hard to tell, but I don't think Ke$ha is even in it.
90% sure this is fake. Ke$ha is barely on it so I dont think it's really her. And Pixie's voice sounds like it did on her early demo's from a few years ago, so this isn't new.