LOS ANGELES (Reuters) “Iron Man” star Robert Downey Jr. injured an ankle on the set of the third film in the superhero franchise, causing delays in production, Marvel Studios said. Downey, 47, who plays billionaire playboy-turned-superhero Tony Stark in the “Iron Man” and “Avengers” movies, hurt his ankle while performing a stunt during filming of “Iron Man 3” in Wilmington, North Carolina, Marvel Studios said in a statement.