'Avengers: Infinity War' Cast News And Plot Spoilers: According to the 'Avengers: Infinity War' co-director Anthony Russo, 'The Defenders' won't make appearance in new Marvel film

"It's complicated. When we start to serialize the telling of stories is difficult," Russo said in a recent interview. "You have to have a lot of control and focus on the course of history. The films are controlled by a group led by Kevin Feige, so they function as a unit. Other products, even if they are from Marvel, are controlled by others. Then there is the possibility of a crossover, but is more complicated."

Robert Downey Jr. started a rumor that he might be making a fourth "Iron Man" film when he appeared on "The Ellen DeGeneres Show" and but backtracked when he appeared on "The Late Show with David Letterman." None of that stopped fans from speculating about the possibility of "Iron Man 4."

The rumors say if Downey turns down the chance to reprise the role of Tony Stark/Iron Man in the "Avengers: Infinity War" movies, someone will be ready to take his place and it might be Ty Simpkins, who played Stark's sidekick Harley Keener in the third "Iron Man" film.

Avengers: Infinity War' is an upcoming two-part installment in the Marvel Cinematic Universe's Phase Three.

'Avengers: Infinity War' is may feature a fight between the Hulk and Captain America as well as a newly forged alliance between the Avengers and the Guardians. Both Heroes appear in "Captain America: Civil War." But Marvel Studios has not yet confirmed if "Iron Man 4" is in the works.

Movie Pilot reports that an impending clash between Hulk and Captain America may be in the works for the latest installment in the Avengers cinematic series.

Chris Evans plays Steve Rogers/Captain America.

"I'd be happy to be in an 'Iron Man' movie. We've been in so many movies together, the titles are almost, at this point, inconsequential. We all win," Evans told Entertainment Weekly.

The first film featured the fight between Avengers members Iron Man and Thor during a disagreement about Loki's fate. Another fight followed between Thor and Hulk when Loki escaped.

Australia Network News suggested Captain America might have to take on Hulk, but Mark Ruffalo's Hulk will not be part of the latest 'Captain America: Civil War' film despite returning for 'Avengers: Infinity War'.

"My character had been in the script, but then he got removed," Ruffalo revealed in a previous interview.

"Who knows, maybe the Hulk will never return. They want to keep the revelation of what happened to him a secret, because it's something really big."

'Avengers: Infinity War' premieres on May 4, 2018 (part 1) and May 3, 2019 (part 2).