(NEW YORK) -- One of the world's biggest stars went toe-to-toe with one of music's biggest names on Saturday, the New York Post reports, when Robert De Niro had it out with Jay-Z at a star-studded birthday bash for Leonardo DiCaprio.
The party, held at The Darby in New York, was also a fundraiser for the Leonardo DiCaprio Foundation, which in part funneled donations to Hurricane Sandy relief. But despite the festive atmosphere, De Niro reportedly gave Jay a public "dressing down" over the music mogul's not returning his calls.
A spy said, "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...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."
The source said Jay tried in vain to "joke his way out," and that his better half, Beyonce, even tried to smooth things over, "but that didn't calm Bob down."
The spy called the exchange "the talk of the party," saying, "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."
De Niro reportedly was upset that Jay didn't return his calls after they agreed that the rapper would record a song for the actor's Tribeca Film Festival.
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