Avengers: Age of Ultron
Iron Man, Ultron and Captain America Marvel

After Avengers: Age of Ultron, Captain America: Civil War will be Marvel's next big film featuring multiple superheroes. And latest reports about the ambitious 'Iron Man vs Captain America' project have revealed some key production updates.

According to The Hollywood Reporter, filming for Captain America 3 will start in the spring of 2015 with actor Jeremy Renner - who plays Hawkeye in the Marvel movies. It is not clear as yet whether Robert Downey Jr and Chris Evans will also be part of the same schedule.

However, with filming set to commence soon, fans can expect a lot more spoilers in the coming weeks.

The Civil War story line deals with the government passing a super-human registration act which forces costumed heroes and villains to register themselves and their real identities. While Tony Stark/Iron Man supports this decision, Captain America is against it - which leads to a superhero civil war.

Meanwhile, Avengers 2 director Joss Whedon recently told SFX magazine how Ultron will be a similar villain to Loki (Tom Hiddleston) in that he'll use his knowledge of each member of the Avengers team to try to defeat them. As Whedon explains, "The only way you can attack Earth's mightiest heroes is from within." (via ComicBookMovie)

"You know, he's really been a mainstay of 'The Avengers' [comics], but for me it's a robot who's angry. And that was a gateway for me to a robot who's completely irrational. I wanted to write a robot that we really haven't seen in this kind of movie, who can basically talk all the logical robot things, but then has hissy fits!"

"He also has a real perspective on who the Avengers are, and a real beef with them. The thing that worked about Loki was that he was able to get inside everybody's head a little bit, and Ultron, he's got the same thing. He knows pretty much everything there is to know about these guys. The only way you can attack Earth's mightiest heroes is from within," the director said.