Joe and Anthony Russo say no fan has ever successfully predicted what happens 'Avengers: Endgame'.

Anthony Russo and Joe Russo

Anthony Russo and Joe Russo

The directors - who have helmed the upcoming blockbuster, 'Avengers: Infinity War' and two 'Captain America' movies in the Marvel Cinematic Universe - admit some fans have "got kind of close" to guessing plot details of the superhero flick, but nobody has ever calculated "exactly" what will happen in the movie, which is set for release on April 25.

In an interview with Jake Hamilton, Anthony said: "Here's the thing, the fans are so passionate and they spend such a long time living with these characters, thinking about these characters, and they're using their imaginations to follow where these stories could possibly go.

"Sometimes they're wildly off; sometimes they're kinda next door to what might happen ... Here's the thing, nothing's ever that close. You can get kinda close, but it's never exactly."

Joe added: "Our mission's always to surprise people. So we try to make really surprising choices."

The filmmakers went on to explain that cast members - who include Robert Downey Jr, Chris Evans, Tom Holland, Benedict Cumberbatch and Scarlett Johansson among many more - are given information on a "need to know" basis and are given all the necessary context to "understand their character arc" but they feel as though they're doing the actors "a favour" by keeping plot details under wraps as "it's difficult" knowing Marvel secrets.

Joe said: "It's definitely based on what the actor needs to know to understand their character arc and what they're doing in the movie.

"Even if we're not giving them everything we wanna give them context so that kind of guides everything.

"But we treat it as a need to know so as long as you understand where you are in the movie what your needs are as a character, you don't really need to worry about everything else.

"We always look at it like it's a favour we're doing the people - it's hard to have all this information that you can't talk about it's really difficult you have to constantly mind yourself."