By Phil de Semlyen | Posted 22 Mar 2016

A war movie? An action thriller? A super-powered face-off for the ages? However you’ve heard Captain America: Civil War described, you’ve probably only heard it called a love story in semi-jest. But that's exactly how director Joe Russo termed it when Empire caught up with him on set.

“What’s fascinating about the Cap-Bucky story as well is it’s a love story,” says the co-director. Stop your sniggering at the back, he’s talking about the fraternal kind. "These are two guys who grew up together, and so they have that same emotional connection to each other as brothers would, and even more so because Bucky was all Steve had growing up.”

The picture, of course, is clouded by Cap’s guilt and Barnes’ ambiguous morality. "Is he good or is he bad?” ponders Russo. "Steve has to answer that question for himself, and there are other characters in the movie who hold the opposite point of view. It becomes a very explosive. It incites a lot of conflict."

Bucky himself, Sebastian Stan, dials back a little on the love talk - hey, it’s not like that fan fiction needs help writing itself – instead likening the pair’s relationship to the Bad Boys movies’ Will Smith/Martin Lawrence dynamic. "I think it’s easy and generalising it to say that they’re lovers, when you’re forgetting that one has a lot of guilt because he swore to be the protector of the other, the father figure or older brother so to speak, and then left him behind.” Adds the actor: "I have no qualms with it but I think people like to see it much more as a love story than it actually is. It’s brotherhood to me." Science Bros, eat your hearts out.

One thing that is clear is that Cap's loyalty to his old friend, now compromised by that whole Winter Soldier thing, fuels the breakdown of another, more brittle friendship. Tony Stark is, as the movie's most recent trailer shows, is a foe to be reckoned with.

Joe and Anthony Russo are directing this one, from a script by Christopher Markus and Stephen McFeely. It stars (deep breath): Chris Evans, Robert Downey Jr., Scarlett Johansson, Anthony Mackie, Emily VanCamp, Don Cheadle, Jeremy Renner, Chadwick Boseman, Paul Bettany, Elizabeth Olsen, Paul Rudd, Frank Grillo, Tom Holland, William Hurt, and Daniel Brühl.

Captain America: Civil War lands in the UK on from April 29, and US cinemas from May 6.