I'm pretty sure Joss Whedon had this exact conversation somewhere:
"You know, I've pretty much managed to gain the undying admiration of all of geekdom. Except for one guy. Hudson Shock. It just galls me that he's managed to elude me all this time. He never got into Buffy the Vampire Slayer. And he didn't watch Firefly, either. What's up with that?
"I've got to get this guy. Igor, hand me his psychological profile. What can I work with here? Mad scientist supervillains? Sure, I can do that? Musicals? Yeah, why not?
"But that's not enough. This time, I've got to make sure I've got him. Wait, what's it say here? He looks almost identical to Neil Patrick Harris (only more brutally handsome)?
Then, by God, GET ME NEIL PATRICK HARRIS!
"It'll be like we're casting Mr. Shock himself in the role he, frankly, was born to play, if only he'd had the good sense to have been an actor instead of an international man of adventure."
Well played, Mr. Whedon. Well played indeed.