Ryan Gosling as Batman? It could happen!

This past weekend at San Diego Comic-Con, director Zack Snyder dropped a bomb that reverberated throughout the movie industry and into the blogosphere: the sequel to his latest film, Man of Steel, will feature not only Superman, but Batman as well.

While the two superheroes have never appeared together in a movie, their stories have long been intertwined through joint appearances in DC comics titles like World’s Finest and Justice League of America. And for much of their careers, Superman and Batman worked together as staunch allies in the struggle for truth, justice, and the American way.

That narrative began to change, however, in the 1980s when some DC titles began to show a grittier side to the Batman story, as well as an adversarial element to the character’s relationship with Superman.

Clearly, it’s this branch of the mythology that Snyder will be exploring. To give fans a feel for what he has planned, Snyder brought Man of Steel actor Harry Lennix (General Swanwick) on stage—with reading glasses and an ascot—to read a passage from Frank Miller’s groundbreaking 1986 comic series, The Dark Knight Returns

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

With Henry Cavill (Superman), Amy Adams (Lois Lane), and Laurence Fishburne (Perry White) already on board, the big question is, who will play the Caped Crusader?

The last actor to play Batman, Christian Bale, has all but said he’s finished with the role, leaving the field wide open. And, if nothing else, the ages of the previous Batmen—Adam West (84), Michael Keaton (61), Val Kilmer (53), and George Clooney (52)—keep them out of the running.

With Henry Cavill still not a household name, Snyder may go for a heavyweight as Batman to counter Robert Downey Jr.’s Iron Man.

So who would make a good Batman? Well, if the noir tones of Miller’s Dark Knight are setting the mood, then it will have to be someone who knows how to brood. Perhaps Michael Fassbender, Ryan Gosling, Mads Mikkelsen, or even Benedict Cumberbatch.

It could even be the obvious choice: Joseph Gordon-Levitt, whose character of Robin Blake stood as the spiritual successor to Batman at the end of Christopher Nolan’s The Dark Knight Rises. After all, it seems likely that Nolan’s Batman and Snyder’s Superman inhabit the same universe: Nolan produced Man of Steel, Chicago stood in for Gotham and Metropolis in both cases, and the look of Snyder’s film appears carefully manicured to dovetail with the latest Batman trilogy.

Only time will tell, but with a summer 2015 release date we should know the not-so-secret identity of the new Batman sooner rather than later.