The final, coordinated assault on Thanos(Josh Brolin) could last as long as three hours, according to Avengers 4 co-director Joe Russo. The filmmaker talked about the movie's runtime during a live Q&A on the Instagram of Duello, a bar that just opened in his Los Angeles-based restaurant, Simone.
“The running time on Avengers 4 is currently sitting right at three hours. We’ll see if that holds,” he said, adding that they're only halfway through the editing proces and just "sratching the surface" with over 3,000 VFX shots. Full story HERE