Captain America: Civil War may or may not receive a visit from the Hulk. Mark Ruffalo isn't quite sure.

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Cap's (Chris Evans) next outing will on the Avengers en force, but it remains unclear whether or not Bruce Banner will be on the roll call. Hulk went off on his own at the end of Avengers: Age of Ultron, and his intentions remains unknown. If the Avengers rally once more, however, there is always a chance the green rage monster will be drawn back into the fight.

"I don't know! I heard a rumor about that the other day," Ruffalo told Collider of his possible Civil War involvement. "I haven't seen a script, nobody's told me, and I don't have dates. But I can only hope so!"

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The 2016 superhero flick will see the First Avenger and Iron Man (Robert Downey Jr.) go head-to-head over the Superhero Registration Act. Joining in the battle will be Hawkeye (Jeremy Renner), Black Widow (Scarlett Johansson), Scarlet Witch (Elizabeth Olsen), Falcon (Anthony Mackie), Black Panther (Chadwick Boseman), Winter Soldier (Sebastian Stan), Ant-Man (Paul Rudd), Vision (Paul Bettany), Crossbones (Frank Grillo), and Baron Zemo (Daniel Bruhl).

Find out more when Captain America: Civil War hits theaters on May 6. Click the video below to see a preview for Cap's last film, Winter Soldier.