This weekend, Robert De Niro slapped Donald Trump’s “crazy” behavior with a piece of advice: "Don’t go out there and say things unless you can back them up." Appearing on Fox & Friends today, Trump had some choice words about the actor, notes Mediaite: “He’s not the brightest bulb on the planet,” the potential GOP candidate said. “I like his acting,” but “when I watch him doing interviews and various other things, we’re not dealing with Albert Einstein.” Watch the clip; the De Niro discussion starts around 2:55. (More Donald Trump stories.)