Tensions were high at Leonardo DiCaprio's birthday party at The Darby in the West Village, as Robert De Niro reportedly got into a heated conversation with Jay-Z. De Niro was reportedly upset after Jay-Z promised to record a song for the Tribeca Film Festival, but never returned his phone calls.

A source at the party told the New York Post, "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. Bob wasn't in any mood to make polite conversation," the spy 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 allegedly tried to make a joke of the situation, telling De Niro he's terrible on the phone, according to a source, who added "De Niro kept telling him that he thinks he's the man, but that he was disrespectful.'"

At the climax of the argument Beyonce came over to try and cool the situation, but things were already in full swing, according to the source.

Afterwards, the source said the party was in an uproar over the incident, claiming "It was the talk of the party. 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."

A source close to De Niro revealed, "It was a low-key private conversation between two people that was apparently overheard. It was not a heated discussion."

Source: New York Post