Anthony and Joe Russo considered "borrowing" characters from the Netflix Marvel shows for 'Avengers: Infinity War'.

Anthony and Joe Russo

Anthony and Joe Russo

The directing duo's blockbuster included numerous Marvel Cinematic Universe heroes outside of the traditional Avengers squad, such as Spider-Man (Tom Holland), Doctor Strange (Benedict Cumberbatch) and Star-Lord (Chris Pratt), and now Joe has admitted there discussions to include some of the TV characters from 'The Defenders', 'Daredevil', 'Jessica Jones', 'Luke Cage', 'Iron Fist' and 'The Punisher' programmes.

Speaking to Collider about why none of the Netflix heroes made it into the final script, Joe said: "Yes, of course we talked about all that stuff but you can see how many characters there are in the film. It's very difficult when you've got shows that are being written when you're also trying to create movies that are not happening on the same, just from a production standpoint, at the same time that the shows are being produced. It's impossible for us to correlate story between three or four other marvel films that we're borrowing characters from and then to add the TV shows in on top of it. It just becomes an experiment that would break. We felt that the best way to tell the story was to stay with the Marvel Cinematic Universe."

'Avengers 4' is due to hit cinemas in May 2019 and Marvel veteran Mark Ruffalo, who portrays Dr. Bruce Banner and his giant green alter ego the Hulk, has previously admitted the ending for the movie is undecided.

He said: "We don't even know what it's gonna be yet. We're not just doing re-shoots. We're going to finish the movie, which we really didn't get to finish totally when we left it last year.

"I don't even know that [the Russos] really know exactly. Some of it is happening while we're there. It's pretty amazing. And we'll shoot some stuff and a few days later come back and reshoot it 'cause we wanna take it in another direction. It's a very living organism; even as we approach it being a locked picture, we're still working on it."