By Jeff Labrecque
April 12, 2012 at 02:41 PM EDT
Matt Sayles/AP

At last night’s world premiere of The Avengers in Hollywood, the red carpet was packed with huge movie stars. But of course, that was the point, since The Avengers brings together several heroes from the Marvel universe to form a superteam to defend Earth. Iron Man, Thor, Captain America, and the Hulk already have their own franchises, and Black Widow and Hawkeye are poised to break out, but did the cast ever doubt that all these characters could fit in one movie. Yes, actually. “If I’m being honest, I thought there were going to be too many in Avengers until we read the final script,” said Scarlett Johansson. “I just didn’t know how you’d successfully tell the story of two mercenaries, a mutant, a couple of Gods from outer space, a hero frozen in time, and a cocky playboy with a super suit. It just didn’t make sense that they would all fit together. But Joss did an incredible job of blending the storylines. When I first met him, he said, ‘These characters should not exist in the same movie.’ He got it out there on the table and once he faced that demon, said what everyone was thinking, it was a lot easier to accept the unbelievable reality of it.”

Clark Gregg, who’s played S.H.I.E.L.D.’s ubiquitous Agent Coulson in previous Marvel-hero films, also had concerns. “I thought if there was ever a film where there were too many capes in one room, this was going to be it,” he said. “But then I read Joss’ script and then saw bits and pieces and then saw the film. Somehow it feels like the whole point of the movie. Like, it is so natural for all these characters to work together. It actually reminds me of movies I loved as a kid like The Dirty Dozen. You can’t help but get swept up in the camaraderie.”

Whedon’s knowledge of the Marvel universe clearly was the difference.I’m amazed that they could fit so many stars as they did here into one movie and actually make the story work,” said Stellan Skarsgard. “But Joss did a great job. Everyone gets their moment. Even the professor.”

I’ve been reading The Avengers comic since I was 14 so it wasn’t like I had to Wikipedia the characters or anything,” said Whedon. “But there is still a fair amount of research involved especially because you have to take into consideration where the other films left off and setting up for future films. And I really cared about these characters as a fan so I wanted to get it right or at least as much of it as possible.”

So did he get it right? Only one guy would know for sure.

“Joss Whedon will have done a good job with it because he gets it,” says Marvel godfather Stan Lee. “He’s a fan. There has never been this many characters from pop culture in one film, and I think it is going to be a monster hit — mainly because of my cameo, of course.”

Like Skarsgard said, everyone gets their moment.

(Reporting by Carrie Bell.)

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