De Niro, Jay-Z Fight in the Middle of Celeb Party Happy birthday, Leonardo DiCaprio By Evann Gastaldo, Newser Staff Posted Nov 15, 2012 9:51 AM CST 45 comments Comments Robert De Niro poses for a photograph on the red carpet at the gala for the new movie "Sliver Linings Playbook" during the 37th annual Toronto International Film Festival in Toronto on Sept. 8, 2012. (AP Photo/The Canadian Press, Nathan Denette) (Newser) – It doesn't get much more epic than this: Robert De Niro and Jay-Z had a verbal throwdown at Leonardo DiCaprio's celebrity-filled birthday party, sources tell the New York Post. Sources say the rapper approached the actor at his table to say hello, and De Niro was having none of it. He "told Jay that he never called him back," a source says. Witnesses say the argument had something to do with a song Jay-Z said he would record for the Tribeca Film Festival. "Bob wasn’t in any mood to make polite conversation," a source says. "He told Jay that if somebody calls you six times, you call them back. It doesn't matter who you are, that is just rude." Jay-Z tried to joke that he's bad on the phone, but De Niro didn't back down and called him "disrespectful." Even Beyoncé, who tried to intervene, wasn't able to restore the peace. "It was the talk of the party," a source says. "Everyone was saying there’s only one star in New York bigger and badder than Jay-Z, and that's Robert De Niro. He can be quite scary when he's angry."