Chris Evans and Scarlett Johansson Talk Romance and 'Running Rogue' in 'Avengers: Infinity War' (Exclusive)

ET sat down with the Marvel stars on set to discuss Captain America's Secret Avengers and the upcoming 'Black Widow' movie.

"We're in sort of bits and pieces all over the place," Scarlett Johansson announced of the state of the Avengers leading into Avengers: Infinity War, "which sounds a lot more gruesome than it actually is."

Not that the schism in the super-group, ongoing following the events of the last Captain America movie, wasn't brutal, with Iron Man (Robert Downey Jr.) and Captain America (Chris Evans) exchanging blows before going their separate ways. "Since we left Cap in Civil War, he dropped the shield and went rogue," Evans told ET's Brooke Anderson on the Atlanta, Georgia, set of Infinity War. "He's been off doing missions by himself with Black Widow with Falcon, and he's kind of answering to nobody."

All of which sounds an awful lot like the Marvel Cinematic Universe's take on Captain America's "Secret Avengers" from the comics, with Steve Rogers taking on a version of his Nomad persona. It also explains the duo's new looks: a covert blonde bob for Black Widow and rugged beard for Cap. (Which Evans had to partially shave off for his appearance in Spider-Man: Homecoming and then quickly regrow. "He took prenatal vitamins," Johansson joked. "That's a little-known fact.")

"Our characters have been part of some counterterrorism efforts, but we're flying under the radar. It's a lot," Johansson elaborated, "when you are on these kinds of missions with no governmental support. You don't really have the support of even the general public and you're sort of running rogue, trying to do what you know is best for the common man but you don't have someone to guide you." Meanwhile, the other Avengers are dealing with the fallout from Spider-Man and Thor: Ragnarok. "There have been a lot of changes that have gone on since the original Avengers assembled, reluctantly."

"There have been a lot of changes that have gone on since the original Avengers assembled."

Infinity War will see the Avengers assemble alongside the Guardians of the Galaxy and the cast of Black Panther, as well as Doctor Strange and Spider-Man, to fend off a galactic titan hell-bent on obliterating the universe. As for which characters Evans and Johansson cross paths with, neither will name names, but they do provide some context clues. Of having the wise-cracking Chris Pratt and Downey together, Evans weighs in, "I think they do a good job of sprinkling those guys around. Add a little bit of spice into each group." Of the greater female presence on this film, Johansson exclaimed, "Thank God!" then added, "I haven't really had the opportunity to work with [many], other than Danai [Gurira]...It still feels like I'm surrounded by dudes all day."

"We haven't had the opportunity to work with probably 75 percent of those 60-whatever people," she continued of the movie's massive cast. "Just because their characters are off in some other--" "Realm," Evans cryptically finished. In fact, when quizzed to see how many of the 64 Marvel characters featured in Infinity War they could name in 30 seconds, both instantaneously, amusingly, became overwhelmed.

"Oh, my God," Evans laughed. "I don't know if I could. God, my brain just broke trying to do it. Captain America, Black Widow...That's all!"

Whaddya know? Those are the only two characters required to broach another subject fans have been speculating about since The Winter Soldier: Whether there is any romance between Steve Rogers and Johansson's Natasha Romanoff, who shared a kiss while undercover on a mission, before Natasha and Bruce Banner (Mark Ruffalo) became star-crossed in Age of Ultron. "I don't think a romance has ever really been in the air for these two," Johansson said. "Sorry to disappoint."

"I agree," Evans said. "I think there's a functionality there. There's a void that they each fill for each other, and I think they've each kind of had to face a little bit of, like, a destruction of a belief system along the way. They've each leaned on one another for different reasons. I think in a lot of ways Cap certainly looks up to Black Widow. She's always been a little wiser, a little more experienced, a little more callused in the way the world really is…I think in the past couple of years, before we pick up in this film, they've really kind of become this rock for one another."

"They have such a mutual respect for one another, personally and professionally, that I don't even think there's room for a romance in this," Johansson agreed. "We've got a world to save."

As for what follows Infinity War? Both actors are presumed to survive until the untitled fourth Avengers arrives next year. After that, it seems only Widow's fate is guaranteed, as a solo Black Widow movie has been confirmed in the works by Marvel. When asked about the prospects last summer, Johansson understandably played coy, though she did reveal what it would take to get her to sign on.

"I would want to in the right context, for the film to fit where I'm at and where I am in my life," she said. "I've played this character for a long time. It's been probably, like, eight years or more, and so much has happened in my life...I think that there's definitely an opportunity to explore Widow as a woman who has come into her own and is making independent and active choices for herself, probably for once in her life. She hasn't always had that possibility. So, if it fit those criteria, then, yes, I do want to do it."

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