His statement comes after producer Kevin Feige's recent statement that the "Iron Man" film series could still go on with another actor if Downey Jr leaves the franchise someday, reported Ace Showbiz.
"I would really hate for someone else to think they could step into my shoes. I wonder who's playing Tony Stark next. Is it you? Is that what you're here to tell me?" he said.
Though the 42-year-old actor was not sure about how many "Iron Man" movies he could tackle in the future, he did confess that he would stay in the franchise as long as they remain good films.
"I know things are looking like that they could go on for a long while. As usual in my book, it's all about quality and delivering a product that you can have this kind of reaction to. If they keep doing that, maybe I'll keep showing up," he added.