Avengers: Infinity War proved to be quite an epic, uniting the Avengers and the Guardians of the Galaxy, as Thanos finally came to Earth to complete his Infinity Gauntlet and reshape the universe. This mammoth storyline, of course, made it no surprise that the film -- clocking in at 2 hours and 40 minutes -- was Marvel Studios' longest-running movie to date. However, that could change come Avengers 4 next year, because according to the Russo Brothers, the Infinity War follow-up will outdo its predecessor and most likely be longer; hinting that a 3-hour film could be on the docks.

"It's pretty long," Joe Russo said to Collider when asked about an estimated the run-time. "I don't want to say how long it is because people tend to get really excited. Also, I don't know that you can really call it a rough cut, it's more of an assembly."

RELATED: Avengers 4: Everything We Know So Far About Infinity War’s Sequel

"It's our longest rough cut. We have never gotten a time mandate from them at all," he added. "It could easily be a three-hour film but I think that we're very hard on the material, we like it to play at a certain pace, so I'm sure we'll squeeze it. We have a whole year of work left on that movie. I do think it'll be longer than Avengers 3."

Interestingly enough, the directors recently revealed that they haven't even finished shooting the sequel, much less gotten around to a final edit. With this film setting up Phase Four, there are a lot of arcs to wrap, from Captain Marvel joining the fray to another cosmic entity rumored to be in the mix to talks of time-travel and Skrulls appearing, as well as which heroes will be resurrected.

RELATED: Which Infinity War Casualties Will Stay Dead in Avengers 4 (and Why)

Given that several actors' contracts are up, some superheroes may still be slated for death or retirement, too. Either way, with so much still to answer, we fully expect final stand against the Mad Titan to take quite some time as it unravels on the big screen.

Directed by Joe and Anthony Russo, Avengers: Infinity War stars Robert Downey Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Anthony Mackie, Paul Rudd, Elizabeth Olsen, Tom Holland, Benedict Cumberbatch, Chadwick Boseman, Chris Pratt, Zoe Saldana, Dave Bautista, Bradley Cooper, Vin Diesel, Tom Hiddleston, and Josh Brolin. The film is in theaters now.