SAN DIEGO — Joss Whedon could have escaped Comic-Con a hero simply by taking the stage in Hall H on Saturday and announcing the title of his next Marvel flick, "Avengers: Age of Ultron."

But on Sunday at the Con, the director decided to pull back the curtain on his plans for the superhero sequel during a chat with Marvel LIVE, and for that we salute him.

"Age of Ultron," he revealed, will start shooting in London at the end February or the beginning of March (ahead of the film's summer 2015 release date). Read on for the rest of the news Whedon revealed about the film.

'Age of Ultron' Will Not Be Based on 'Age of Ultron

"Age of Ultron," a recent Marvel event penned by Brian Michael Bendis, shot up the Amazon sales chart after Saturday's announcement. Those eager buyers might have acted a bit too swiftly.

"[That's] not the case," Whedon said of basing the movie on the book. "We're doing our own version of the origin story of Ultron....We were crafting our own version of it where [Ultron's] own origin comes more directly from the Avengers were already know about."

Hank Pym Isn't Involved

Since a) an "Ant-Man" movie is in the works, b) Ant-Man is a creator of one version of the robot Ultron, and c) Hank Pym is one alter-ego of Ant-Man, many people assumed Pym would play a role in Whedon's "Age of Ultron." Not true, said Whedon.

"The other thing is in the origin story there was Hank Pim, so a lot of people assumed he was going to be in the mix, but he's not," he said. "We're basically taking the things from the comics for the movies that we need and can use. A lot of stuff has to fall by the way side."

Ultron Was An Obvious Choice

We'll let Whedon take this one: "Ultron has been their chief villain when I read the book. He's been the Avengers villain. I was amazed anybody was surprised it was going to be him in the movie. Since before I even took the job of making the first one: 'I don't know if I want to make this movie but the second one should have Ultron in it.' "

He added of the character's physical appearance in the film, "Ultron is definitely someone who evolves, so we're going to get a couple different iterations."

The Sequel Will Be Darker

The script is almost done, according to Whedon — and it will likely look and feel quite different than the 2012 original.

"It's a little bit darker than the other film since Ultron's in the house," he said. "It's got a sci-fi element to it that's a little bit stronger than the other film. Getting the team together was so rousing. But seriously, keeping the team together is a completely different problem."

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