STORY: Ben Affleck as Batman: Internet's 10 Best Memes

Bieber's photo was "liked" more than 346,000 times just four hours after being posted, and sparked a number of comments from distressed Batman fans, with one young woman declaring "Batman would be ruined forever" and others wondering if the teen star would play Robin.

But not so fast, Bat-fans. Bieber tweeted earlier Friday that he was doing some work with Funny or Die, so perhaps the phony script had something do with that.

PHOTOS: Ben Affleck and 10 Actors Who've Played Multiple Comic Characters

In a fun detail, the script claims to be based on Batman: The Dark Knight Falls – the fourth issue of Frank Miller's 1986 classic The Dark Knight Returns comic book series. The issue features an epic battle between Batman and Superman, and during the Comic-Con announcement of the project, Man of Steel actor Harry Lennix read a passage from the issue, in which Batman revels in his defeat of Superman.

"I want you to remember, Clark," Lennix said, "in all the years to come, in all your private moments. I want you to remember my hand at your throat. I want you to remember, the one man who beat you."

At Comic-Con, Snyder said they were not adapting The Dark Knight Returns, which features an older Batman and Superman.

Warner Bros' still untitled sequel to Man of Steel, starring Henry Cavill as Superman and Ben Affleck as Batman, hits theaters July 17, 2015.