Daniel Radcliffe, also known as Harry Potter himself, is a fan of another franchise with a huge fandom. It turns out that throughout Radcliffe's years fighting Voldemort he has an affinity for another hero's journey fighting darkness. It's only a matter of time before J.K. Rowling tweets out this new tidbit about the Harry Potter universe and the fans go nuts.

Because Radcliffe couldn't casually go to a Harry Potter midnight screening, he wants to live out his fantasy of being just a normal, non-famous fans when Star Wars comes out, so he and Conan brainstormed costumes that will let him go unrecognized and won't confuse people into thinking it's actually a Harry Potter/Star Wars crossover episode. 

Sources: Conan