If you’re in a Starbucks and the guy next to you identifies himself to the counterman as “X,” it’s probably Jay-Z. The mogul/musician was spotted in the branch on 49th and Madison, where he was overheard politely placing an order for a venti hot chocolate. A spy reports that when the barista asked his name — for it to be called out when his order was ready — Jay-Z replied “X,” adding, “I know, it’s not a name, it’s a letter, I know.” He then picked up his order at the end of the counter and stealthily slipped out unnoticed by the staff.