Marvel Studios say they want to keep Robert Downey Jr in his Iron Man role "for many years to come".
Studio President Kevin Feige has compared Tony Stark's potential to that of James Bond - insising that the role could pass to other actors in the future.
"Well, look, I don't think Robert will be playing this character for another 30 years, and I certainly hope the character stays in movies for the next 30 years - just like James Bond," he told The Huffington Post.
"I would say before George Lazenby and Roger Moore, Sean Connery was James Bond. It will take a while to fill any shoes, whether it's filmmaker shoes or writer shoes or certainly actor shoes.
"I think Tony Stark is an interesting enough and rich enough character that he can persevere.
"That being said, I hope that doesn't happen any time soon. It certainly is our plan to continue to have Robert Downey in the persona of Tony Stark for many, many years to come."
There has been some uncertainty about the future of the Iron Man franchise following the recent release of the third film as Downey revealed that his contract with Marvel has expired and felt unsure about his future.