The Avengers: Age of Ultron will bring back the Science Bros., but Bruce Banner and Tony Stark won't get along as well as some would hope.

'Avengers 2' Hulkbuster Battle To Be Emotionally Charged, Why Will Iron Man & Hulk Fight In 'Age Of Ultron'

The Hulk (Mark Ruffalo) and Iron Man (Robert Downey Jr.) may be working side by side when Avengers 2 kicks off, but Banner's misgivings about Starks' Ultron project will start to cause lasting tension between the two geniuses.

"Stark has set Banner up in order to be able to continue his good works in Stark Tower," Downey Jr. explained to Entertainment Weekly at the 2014 San Diego Comic-Con. "Tony has a project of his own. So it's one of those things where it's like a development team - 'Hey how's it going over there? That looks nice and green. Can I talk to you about this other idea I have?' But it winds up not being such a good idea."

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Clearly. There wouldn't be a film if everything went according to plan.

"Bruce is dubious as to the moral psychology of this project idea of Tony's," Downey continued. "It's nice because it sets up a little bit of tension between us."

Will this tension result in the upcoming Hulkbuster battle? Clearly Banner's concerns about Ultron will turn out to be correct, but will he choose to air those grievances on the streets of Johannesburg?

Find out more when Avengers 2 enters theaters on May. 1. Click the video below to see a teaser for the upcoming film.