Iron Man is back for the Avengers: Age of Ultron, but how long will Robert Downey Jr. stick around?

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The face of Marvel's Iron Man franchise is busy working on Joss Whedon's follow up to 2012's The Avengers, but Downey is continuing to hint at the possibility that he may be getting too old for the superhero role.

"The smart money is you have to look at everybody's age. I'll put myself at the top of the list," Downey explained to Variety. "Sooner or later, they've got to start over and get somebody young. I'm not there with them yet. It really is the closest thing to being a beloved contract player with a big old-timey studio that there is right now. When you really think about it at the end of the day, these films are entertainment largely driven by young folks."

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If Downey were to leave Iron Man behind, who would take over his role? Would Marvel simply replace the actor in the style of James bond or would Tony Stark die so that another character could don his armor? According to recent rumors, it looks like Marvel would probably learn more towards the later option.

Fortunately for Iron Man fans, Downey still has one more Marvel film on his contract after the 2015 release of Age of Ultron.