Jay Leno Jay Leno

Things are getting tense between NBC and Jay Leno. Amid reports that the network is planning to replace him as the host of The Tonight Show next year, Leno went after NBC in his opening monologue on Monday.

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"Well, you know, the whole legend of St. Patrick, right?" Leno said. "St. Patrick drove all the snakes out of Ireland, and then they came to the United States and became NBC executives."

This isn't the first time Leno has made unflattering jokes about NBC. On Feb. 28, the comedian referenced the network's ongoing ratings struggle."For the first time in history, NBC is going to finish fifth in the ratings period," Leno said. "We are behind the Spanish-language network Univision — or as we call it here in Los Angeles: Cinco de Ratings." He then went into a series of quick one-liners about the network, including, "it's so bad,

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Leno's new dig came three days after The New York Times reported that NBC Chairman Robert Greenblatt had sent an e-mail to Leno complaining about the ratings jokes, prompting "an exchange of pointed e-mails" between the pair. One of the three sources the Times quoted said that Leno was surprised by Greenblatt's displeasure and defended himself by saying that late-night stars ribbing "their masters" is a long-standing tradition.What do you think of Leno's joke? Do you think NBC has a right to be mad at Leno?