It has been a long talk between Marvel and Robert Downey Jr. if he's going to reprise his role for the much-awaited "Iron Man 4." It is not yet sure when the fourth installment will be on the works, and unfortunately, it looks like the 50-year-old actor is through with the franchise.

Reports stated that as the American actor is already aging, it will be hard for him to continue his signature role doing heavy stunts. To recall, he was just at the age of 43 when he first took the character of Tony Stark as "Iron Man," according to Master Herald.

Furthermore, there are swirling rumours that RDJ is already tired of portraying the billionaire industrialist and genius inventor. He also hinted that he might retire the role of the playboy philanthropist after the release of "Avengers: Infinity War Part 2" in 2019.

Meanwhile, International Design Times reported, as cited by E! Online that the father-of-three told David Letterman that "There [are] no plans for an "Iron Man 4" when he appeared at "The Late Show" on Oct. 7, 2014. The host asked RDJ if "Iron Man 4" will ever be seen in the big screen by its millions of fans.

"Just between us, no," the husband of Susan Downy firmly said. "But, I'm going to do other stuff with Marvel. I'm still going to be involved with Marvel and there's going to be plenty of fun stuff to happen."

Additionally, Marvel Studios announced in the last quarter of 2015 that they are about to release 14 movies starting in 2016 up to 2020. The first 11 films that they will be releasing up to 2019 will be part of Marvel Cinematic Universe's Phase 3, which will start with "Captain America: Civil War," Master Herald added.

The last three flicks that they will launch in 2020 remains a mystery, but everyone expects that one of them will be "Iron Man 4." However, in a press release made by Marvel, the fourth installment of the robotic superhero is, unfortunately, not in the list, and news starts to emerge that it will eventually be "shelved."