Justin Bieber might have been prepping for a Funny or Die installment or just having some fun on his own when he posted a photo of himself holding a “Batman vs. Superman” script with the caption "#robin??"--a move that sent a collective shudder down the spine of fandom.  Could Warner Bros. be so crass as to choose the teen popster rather than a real actor to play Batman’s sidekick in Zack Snyder’s sequel to Man of Steel?
 
The obvious answer is "not bloody likely."  The photo which shows Bieber holding a personalized script is highly suspect.  In the first place it is doubtful that a finished script for the film even exists at this point, and the idea that Warners would be distributing them all over Hollywood to potential actors and allowing them to post photos like this outside the normal carefully controlled movie publicity channels is absurd.  The script also includes a citation "Based on Batman: The Dark Knight Falls by Frank Miller and Klaus Janson," a reference to the fourth section of Miller and Janson’s classic The Dark Knight Returns that is way too pat.  It’s not the way that credit is typically acknowledged and appears to be a ploy meant to give this ridiculous rumor some faint hint of truth. 
 
The fact is that the upcoming Batman vs. Superman movie is far too important to Warner Bros. and DC Comics to risk trivializing the company’s most important superhero movie franchises with a silly casting gesture that would bring instant ridicule raining down on the project from all quarters.
 
The most likely explanation for the Bieber/Instagram affair is the teen idol’s announced participation in a video for Will Ferrell and Adam McKay’s Funny or Die Website.  Ferrell and McKay are likely having some fun at the expense of comic book fandom, which frankly looked more than a little foolish in its absurd overreaction to the casting of Ben Affleck as Batman in the upcoming Man of Steel sequel (see "Petition to Dump Affleck").