From the new Big Mike & DJ Neptune mixtape 4th Quarter Pressure. Already speculation about it being from Detox since Em fills in for Dre on Dre's verse. (via illRoots)
Download: Eminem, "Number One" (prod Dr Dre)
**Update** Already down! Not saying, just saying, don't go searching for "Number One" when this is official because it's officially going to be called something else.