Geez, Jay, what gives? One minute you're bragging about chilling (hood-forever-style) with Robert De Niro in Tribeca, next you're letting Bobby ring your phone off the hook without picking up or returning his calls. According to New York Post reports, frustration over a half-dozen (!!) of his calls not getting returned by the Jiggaman caused real-world drama when the two New York icons attended mutual pal Leonardo DiCaprio's birthday party. Jay went over to De Niro's table to pay his regards, but the actor "wasn’t in any mood to make polite conversation," quotes a source, who describes the situation as such:

Bob was sitting at a table, and when Jay-Z went over to say hello, De Niro told Jay that he never called him back...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...De Niro kept telling him that he thinks he’s the man, but that he was disrespectful. Beyoncé came over, but that didn’t calm Bob down.

Wow. When even an ambassador as esteemed as Beyoncé can't broker a peace agreement, you know there's some legitimate bad blood there. The same source (who the Post refers to as a "spy," which is awesome) claims that the unreturned calls were in regards to a song Jay agreed to record for De Niro's Tribeca Film Festival, which never materialized due to Hov never getting back to the actor. “It was the talk of the party," quoth the Post spy. "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.”

Yeah, we've seen a couple of those movies before. Shame on a Jigga, really—we hoped Gloria Carter had raised him better than that.