SAN DIEGO – Comic book fans no longer have to imagine what it might be like to see all their favorite superheroes in one place.

They got the chance Saturday at Comic-Con, when the cast of the forthcoming "Avengers" film took the stage. Samuel L. Jackson surprised some 6,000 fans gathered for a Marvel Studios presentation when he stepped out just as it was ending and started introducing the cast of "The Avengers."

Jackson brought out stars Clark Gregg, Scarlett Johannson, Chris Hemsworth of "Thor" and Chris Evans of "Captain America."

He then introduced another surprise guest, Robert Downey Jr., who brought out the rest of the all-star cast, including Jeremy Renner as Hawkeye and Mark Ruffalo as Bruce Banner.

"The Avengers" is based on the comic book series of the same name, which brings various Marvel superheroes together. The film is due in 2012.

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