According to previous reports, Robert Downey Jr. will be reprising his role as Sherlock for the third iteration of "Sherlock Holmes." If the news is indeed true, then the 51-year-old actor will have to work harder to fit "Iron Man 4" into his schedule.

However, lack of updates about the next "Iron Man" has led the fans to worry if there will be a film at all. In fact, the phase three lineup of Marvel Films did not have "Iron Man 4" in its listing. But the fans are still hopeful that from the three unnamed Marvel movies slated for 2020 release, one of them will be "Iron Man 4."

According to an interview with USA Today during promotion of "Captain America: Civil War," the actor did not reveal much about the anticipated superhero film. He said, "I don't think that's in the cards. In a way, it's Cap 3 but for me, it's like my little Iron Man 4."

Meanwhile, the fate of the fourth iteration of "Iron Man" became further ambiguous as the Marvel Cinematic head, Kevin Feige, suggested that they may recast new actors to play the superheroes, citing the case of new Spider Man played by Tom Holland in "Captain America: Civil War," and now "Spider Man: Homecoming." Feige, however, also added that this might not happen in case of other MCU films immediately, including "Iron Man 4," Variety reported.

Marvel Studios already admitted that replacing Downey Jr. as "Iron Man" will be difficult and is hard to see someone else play the iconic character of Tony Stark, as is the case of other Avengers such as Hulk, Thor, Black Widow etc., who have already left an indelible mark in the minds of their fans.

According to other reports, there is also speculation that Tony Stark will be killed in one of the "Avengers" films and will be replaced by a female Iron Man, Riri Williams, also known as Iron Heart in the comics.