Superman may be the talk of the town, but Marvel's "Iron Man 3" is still flexing its muscle in theaters, crossing the $400 million mark Tuesday at the U.S. box office.

Disney's superhero threequel has now earned $1.2 billion worldwide to become the fifth highest-grossing film of all-time.

The film's international cume now stands at $803.9 million, according to Disney, surpassing the total gross of "The Avengers" in China, Russia and Korea.

Starring Robert Downey Jr., "Iron Man 3" is the first of three Marvel features on the horizon. "Thor: The Dark World" bows in late November while "Captain America: The Winter Solder" opens next summer.