THE SCREENING ROOM: Jay Leno and Jimmy Fallon Spoof "Tonight" from West Side Story (Video)

Fans of late-night television know there's a rumble going on at NBC lately with the future of "The Tonight Show" in question as long-time host Jay Leno's contract comes up for renewal.

Jimmy Fallon, who's "Late Night" show follows Leno, has been rumored as the likely successor of the coveted "Tonight Show" throne. NBC has not made any official statements regarding whether or not Leno will continue past 2014, but the comic has made several jabs at the network in his recent opening monologues.

While the media has been buzzing over speculation and insider buzz, Fallon and Leno kept things light in a musical parody of "Tonight" from West Side Story on the April 1 episode of "Late Night with Jimmy Fallon."

Just like the film of "West Side Story," the two comics get a little vocal help, a la Marni Nixon (who famously dubbed vocals for Natalie Wood). 

Here's a look at some late night duet-ing...