It's been argued that if it weren't for how successful Robert Downey Jr. was in his role as billionaire arms manufacturer turned superhero, the Marvel Cinematic Universe wouldn't have grown the way it has, and Downey has turned into Marvel's most prized commodity - but will he join the "Iron Man 4" cast?

Now that there's confirmation that there will be a fourth part to the series about Tony Stark, many are wondering whether Downey will be joining the "Iron Man 4" cast or if he'll be passing down his most famous role to a younger actor, as the star's now 50 years old.

According to Movie News Guide, though, there's good news ahead for MCU fans: Downey will definitely be the star of the "Iron Man 4" cast! Shane Black, the director of the past film of the franchise, has now officially confirmed Downey will be reprising the role.

Christian Post reports that, although it's been officially confirmed that the actor will star in the "Iron Man 4" cast, production has been delayed (and there's no official release date for the movie) as Marvel and Downey's team continue to discuss the terms of his salary, which has been a major source of concern in his past few contracts, including his appearance on next year's "Captain America: Civil War."

According to Master Herald, it seems like to join the "Iron Man 4" cast, Downey is currently asking for his salary to be raised $50 million in comparison to his previous one, which would make sense considering that the last installment went on to make more than $1 billion worldwide, and it seems like everything the actor touches is gold, as he's currently the highest-paid star in the world according to Forbes.

In any case, while the terms are still being reviewed, it's great news to see that Downey's officially part of the "Iron Man 4" cast - though it's unclear if Gwyneth Paltrow will be joining him once more.