03/16/2013 11:46 am ET Updated Mar 17, 2013

Jay Leno Pokes Fun At NBC's Robert Greenblatt And Sparks Controversy Over Ratings

Did Jay Leno go too far? NBC chairman Robert Greenblatt certainly thinks so.

The "Tonight Show" host poked fun at NBC's low ratings when Greeblatt made an appearance on his show in late February.

While Leno's jokes “For the first time in history NBC is going to finish fifth in the ratings period. We are behind the Spanish-language network Univision — or as we call it here in Los Angeles: Cinco de Ratings” and “It’s so bad, 'The Biggest Loser’ isn’t just a TV show anymore; it’s our new motto" appeared to all be in good fun, Greenblatt wasn't pleased.

After rumors began to swirl that Leno might be leaving NBC, Greenblatt sent an angry email to the talk show host which sparked a series of tense emails between the two.

NBC hasn't divulged any details on the emails, but there's no doubt that the network has seen better days. While it once boasted high ratings with Thursday night comedies like "Friends" and "Seinfeld," it now sees serious ratings struggles on a weekly basis.

Most recently, the heavily-marketed "Smash," which has seen consistently low ratings, was given a Saturday timeslot.

“I didn’t see it coming, being relegated to Saturday,” showrunner Jonathan Safran told TVLine. “We’re all aware the show is not successful, but I guess I had hoped we would see what happened when The Voice came back [or] maybe they’d move us to a better time slot. But I understand from the network’s point of view. We hit a number and we stuck there.”

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