In the age of superhero films, the name Robert Downey Jr. and Tony Stark seem interchangeable at this point. But speculations have been adamant that the star will not be reprising his role in the rumored "Iron Man 4."

Fans will definitely be disappointed should Downey Jr. not return to the silver screen in a fourth standalone "Iron Man" flick. After all, he can be credited for igniting the superhero frenzy and is practically irreplaceable as Tony Stark. This has not stopped reports from circulating claiming that RDJ might not be behind the iron suit once "Iron Man 4" kicks in.

Given the actor's age and expensive salary, Marvel might choose to cast a new Iron Man for the fourth installment or do away with the superhero altogether. Downey Jr. himself seems interested in continuing on with the role, though.

Should Tony Stark hang in the armor for good, the fourth "Iron Man" film may get a new lead in the form of Natasha Romanoff a.k.a. Black Widow. And although Scarlett Johansson does a good job in portraying the character, it remains to be seen if Natasha will be accepted by the fans as the new Black Widow.

Another rumor has to do with the film's plotline. Some believe that "Iron Man 4" may serve as a prequel rather than a sequel, focusing on Tony Stark prior to the events of "Captain America: Civil War." It could also shed some light on Tony and Pepper's (Gwyneth Paltrow) dwindling relationship.

As for a release date, there are numerous reports assuming a 2020 premiere, after "Avengers: Infinity War." However, no such thing has been confirmed by Marvel yet, so fans should take the news with a grain of salt.

Downey Jr. is still set to play the iconic Tony Stark in the "Infinity War" films, alongside a superhero ensemble boasting several big names, so fans still have time to cope should the rumor concerning his departure prove to be true.