Several theories about "Iron Man 4" surfaced online, and Robert Downey Jr. is rumored to be replaced.

Previously, it has been reported that Robert Downey Jr., who portrays the billionaire playboy philanthropist Tony Stark, will be replaced by a new female character named Riri Williams.

TIME has described Riri as "a science genius who enrolls in MIT at the age of 15. She comes to the attention of Tony when she builds her own Iron Man suit in her dorm."

The speculations continued after Downey posted a photo of a woman in his Twitter account with a caption "Get ready for a new generation of Marvel BAMF."

However, fans have been reacting negatively to this speculation.

Another rumor about the superhero that RJY and Marvel Studios failed to make an agreement about the actor's fee for the fourth installment of the franchise, becoming a reason why the movie is still not being confirmed at the very least. It was reported that after the "Iron Man" movie in 2008, RDJ has become the highest-paid actor in the business for three years consecutive, from 2012 to 2015.

Meanwhile, the 51-year old actor shared a picture on Instagram together with some Marvel executives. This gives fans a glimpse of hope that the "Iron Man 4" is still possible to hit the big screen.

The photo showed RDJ together with director Jon Favreau, Marvel Studios president Kevin Feige, Joe and Anthony Russo brothers, actor Tom Holland, and celebrity chef Roy Choi.

"New project @jonfavreau and @ridingshotgunla are working on! (Photo cred: @jimmy_rich, glam cred: @davynewkirk)," said RDJ on his photo.

The group is in Atlanta and filming three Marvel movies: "Spiderman Homecoming," "Guardians of the Galaxy 2," and "Avengers: Infinity War." Downey is said to reprise his role in both Spiderman and Avengers movies.

However, Marvel and Robert Downey Jr. haven't announced or given any official statement about the recent speculations on the film "Iron Man 4".