OK, here’s some box office hilarity for you. Even if it’s only for one night, an adaptation of a 90-year-old novel toppled fanboy favorite Iron Man 3 as the #1 film in America Wednesday. Baz Lurhmann’s The Great Gatsby starring Leonardo DiCaprio became the top–grossing film in North America with $3.9M from 3,535 theaters vs Iron Man 3‘s $3.85M from 4,253 theaters, according to Warner Bros which co-financed with Village Roadshow and is distributing worldwide. Gatsby‘s 6-day cume is now $63.3M. “It’s a stunning box office upset for the ages,” one exec gushed to me this morning. On the other hand, Disney/Marvel’s Iron Man 3 opened two weeks earlier in the U.S. and three weeks earlier overseas and should pass $1 billion in worldwide gross today and $300 million in North America. And let’s not forget that IM3 lost tickets to the opening of Star Trek Into Darkness last night. Its cumulative performance to date is international $691.9M and domestic $298.6M for a global total of $990.5M. Iron Man 3 is now the 2nd highest grossing superhero movie of all time overseas behind Marvel’s The Avengers and currently stands as the #11 highest grossing film of all time in the international marketplace. By country: China $102.4M, Korea $55.6M, UK $49.7M, Mexico $43.6M, Russia $40.2M, Brazil $39.0M, France $36.4M, Australia $33.7M, Japan $21.4M, Italy $19.8M, Taiwan $18.4M, Germany $18.4M, Indonesia $14.6M, Philippines $14.3M, Hong Kong $13.1M, other markets $171.4M.