After hinting about the fourth instalment of “Iron Man” franchise, actor Robert Downey Jr. has come out clean and said it is not happening.The 49-yer-old actor shared the information on “Late Show with David Letterman” Tuesday, reports eonline.com. "There (are) no plans for an 'Iron Man 4'," he said. “That's a valid question. Like it hasn't made enough money? Yeah, I guess they have too much money or something. There is no script for 'Iron Man 4'. They do have a plan and I think they're going to announce it (soon)," the star responded when asked why the movie is not happening. The actor featured in all “Iron Man” movies, which is based on Marvel comics and produced by Marvel Studios.“But, I'm going to do other stuff with Marvel. I'm still going to be involved with Marvel and there's going to be plenty of fun stuff to happen,” the star said.