Robert Downey Jr. and Mark Ruffalo Didn't Always Know What Their Marvel Dialogue Meant

Robert Downey Jr. and Mark Ruffalo weren't entirely sure what their characters were saying.

The Marvel Cinematic Universe is a franchise intricately connected between its entries, with one film or television series featuring plot threads and characters that first popped up in previous projects. Not only is the MCU itself a sizable shared universe, but it also happens to be based on one of the biggest fictional universes ever dreamt up. That's why to some, following along with the latest Marvel release may be more complicated than typical cinematic releases; including Marvel stars Robert Downey Jr. and Mark Ruffalo.

"Well, I mean, in the Marvel days, everything might change or we're talking to a tennis ball. You and I, the science bros, we would've these long passages about absolute gobbledygook," Downey told Ruffalo in Variety's latest Actors on Actors. "But still it's important to us because we know it's important the characters."

After Ruffalo pointed out the "bullsh-t" helped them with developing their characters, Downey admitted the experience across his Marvel films helped him with his lauded role in Christopher Nolan's Oppenheimer.

"Yeah, it'd be really hard to dig in. I mean, we would just drive each other insane on set going, why can't I retain this? But again, we know when it's time to tighten things up a little bit," Downey continued. "Anyway, I found great joy in [making Oppenheimer]. It was this moment where we were shooting something in Pasadena and Nolan just put this mag of 70 millimeter [film] — they were changing out mags, and he was like, 'Hold this.' And he just put it on my lap."

Is Iron Man returning to the MCU?

Despite rumors suggesting Robert Downey Jr.'s Iron Man may be returning in Avengers: Secret Wars, top Marvel brass have since debunked the notion. Marvel Studios boss Kevin Feige has shut down rumors the production house was thinking of bringing Stark back through multiversal storytelling.

"We are going to keep that moment and not touch that moment again," Feige shared. "We all worked very hard for many years to get to that, and we would never want to magically undo it in any way."

"We'd already said tearful goodbyes on the last day of shooting. Everybody had moved on emotionally," Joe Russo added. "We promised him it would be the last time we made him do it-ever."

Avengers: Endgame, and all other Downey and Ruffalo-starring Marvel films, are now streaming on Disney+.

Do you think Iron Man should return? Why or why not? Let us know your thoughts in the comments section below!