After three successful Marvel stand alone films, there's no doubt that Robert Downey Jr. as Iron Man works.

While the return of the "Sherlock Holmes" actor for a fourth installment hasn't been officially confirmed, RDJ, in previous interviews hasn't put the possibility to rest. He confirmed that he will continue to do projects with Marvel but wouldn't specify if it involves another Iron Man film.

As the world continues to wonder if there will be more solo adventures for the billionaire genius, an earlier statement by one knowing insider reveals that the 50-year-old Hollywood A-lister will revive his role as Tony Stark/ Iron Man for the fourth film which is said to be due out in 2018.

"I think he'll be back for another one. I'm sure of it," quoted Unleash The Fan Boy of director Shane Black after the release of "Iron Man 3."

In related news, Yibada also reported that in line with speculation for another film, the cameos of RDJ in other films indicate that Marvel will set up another Iron Man film.

The publication note that after his appearance on "Avengers: Age of Ultron," RDJ is set to appear in other MCU films that include "Captain America: Civil War" as well as "The Avengers 3."

The site further reported that with all the rumored upcoming roles, "some rumors consider the probability of using such cameo roles as hints at what fans can expect in 'Iron Man 4'."

"Captain America: Civil War"

RDJ's next Marvel big screen appearance will be the third Captain America film where he plays Chris Evans' (Cap) main antagonist. He spoke about the role, as quoted by Comic Book Movie, and the direction Iron Man will go following the events of "Age of Ultron."

"The clues are in Ultron about where we might find him next. But what would it take for Tony to completely turn around everything he's stood for, quote-unquote, because he was the right-wing guy who could still do his own thing. When the first Iron Man came out the liberals and conservatives were both like, 'You're our guy'. Yes! Score! But the idea of Tony being able to march into Washington and say, 'I'll sign up', wouldn't have made sense if the political climate in the real world hadn't shifted the way it has. It's a little bit of things following a real world continuum in, 'What would you do?' There's always the bigger overarching question, that Joss brings up all the time..."

"Civil War" hits theaters on May 6, 2016.