Robert Downey Jr. thought playing Iron Man for a decade was going to ruin his acting chops: 'You start to wonder if a muscle you have hasn't atrophied'

• Robert Downey Jr. thought playing "Iron Man" for over a decade was going to affect his acting skills.
• "You start to wonder if a muscle you have hasn't atrophied," Downey told The New York Times.
• Downey said he was "a hundred percent" concerned about doing Marvel movies for too long.

Robert Downey Jr. said he worried that playing Iron Man for more than 10 years, in Marvel movie after Marvel movie, was going to make his acting much worse. 

Speaking to The New York Times for an article published on Sunday, Downey acknowledged how he hadn't starred in a major role that wasn't the Iron Man franchise's Tony Stark. 

"You start to wonder if a muscle you have hasn't atrophied," Downey told The Times.

Downey, who is set to appear in Christopher Nolan's next movie "Oppenheimer," said he was "a hundred percent" concerned about stepping into a role that didn't involve the Iron Man suit. 

"I knew there was a point where Chris Nolan was endorsing, let's work those other muscles, but let's do it while rendering you devoid of your usual go-to things," Downey told The Times. 

The Golden Globe-winning actor made multiple appearances as "Iron Man" between 2008 and 2019, including the "Iron Man" trilogy and all four "Avengers" films. Downey is credited for helping turn Marvel Studios into a cinematic powerhouse with his portrayal of Stark, a billionaire inventor and world-saving superhero. 

"We wouldn't have a studio if it wasn't for him," said Marvel Studios president Kevin Feige said of Downey during an interview for the 15th anniversary of the first "Iron Man" film. 

Representatives for Downey did not immediately respond to a request for comment from Insider sent outside regular business hours.