It is the news for which superhero fans have always longed: Superman and Batman are to appear together in the same film for the first time.

At San Diego’s annual Comic-Con this weekend, the Man of Steel director Zack Snyder revealed that DC Comics’ best-known heroes will meet on the big screen – and will be fighting each other.

“Let’s face it, it’s beyond mythological to have Superman and our new Batman facing off, since they are the greatest superheroes in the world,” said Snyder, who will direct the as-yet unnamed film, scheduled for release in summer 2015.

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An intriguing passage from the as-yet unfinished script has Batman saying: “I want you to remember, Clark [Kent, Superman’s alter ego], in all the years to come ... In 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.”

Recent films that have united comic book heroes have proved successful. The Avengers made $1.5bn at the worldwide box office. Snyder’s reimagining of Superman in Man of Steel, starring the British actor Henry Cavill, has grossed $621m worldwide.

Warner Brothers confirmed that Cavill would be reprising the role in the new film, but the role of Batman is yet to be confirmed. Christian Bale, who played the Gotham City crime-fighter in Christopher Nolan’s recent trilogy, has said he does not intend to do it again.

Speaking at the comic convention, fan Benjamin Ha said bringing the two superheroes together would cause fireworks. “They’re both alpha males,” he said.