Avid fans of the "Iron Man" series aren't satisfied with just three films. So, the question is, will a fourth installment starring Robert Downey Jr. ever be produced?

In an interview with Entertainment Weekly on the set of "Avengers: Age of Ultron," Robert was asked if he is open to wear the Iron Man suit again. Instead of answering the question directly, the actor said it all boils down to the producers' decision.

"It's down to Kevin [Feige, Marvel Studios president] and Ike [Perlmutter, CEO of Marvel Entertainment] and Disney to come to us with what the proposal is, and that's on us to agree or disagree," said Downey, who was recently made the highest paid actor according to Forbes. "When things are going great, there's a lot of agreement."

"Right now, this has just been swell, hasn't it?" continued the "Sherlock Holmes" star. "This has been a really good one and it feels good and we're having a good time."

Downey notes that "Iron Man" is in a good place. "It's that thing of: Why give up the belt when it feels like you can barely get jabbed?" Downey told EW.

According to The Wire, enlisting Downey in a film doesn't come cheap. He has signed on for Avengers 2, currently in production and a third film. He has reportedly brought in a whopping $70 - $80 million for the first "Avengers" film with "Iron Man 3" back-end income to boot. This is compared to Chris Hemsworth (Thor) and Mark Ruffalo (Hulk) who brought in $2 to $3 million a pop.

Since there's no official confirmation on "Iron Man 4," fans will have to make do with the upcoming Avengers sequel subtitled, "Age of Ultron," set for release in 2015. According to plot leaks, Ultron is an AI robot created by Tony Stark to maintain the peace. The robot then becomes a deliverer of chaos and ultimately seeks to extinguish humanity.

Aside from Downey, the rest of the original cast will be reprising their roles for the Avengers sequel. Chris Hemsworth will return as Thor, Jeremy Renner as Hawkeye, Scarlett Johansson as Black Widow, Samuel L. Jackson as Nick Fury and Mark Ruffalo as Hulk. New cast additions to the film are Aaron Taylor Johnson as Quicksilver, Elisabeth Olsen as Scarlet Witch and James Spader as Ultron. 

To refresh your memory on the Marvel films, below are the trailers for "Iron Man 3" as well as "Avengers" below: