The bit -- which was reportedly Fallon's idea -- began with a phone call between the hosts, with Leno forlornly telling Fallon, "I'll live I've been through this before. I'll admit I'm a little sick of all this."
After Leno reassured Fallon they would still be friends regardless of business, the two launched into a music duet parodying West Side Story's Tonight.
Fallon: Only you, every night you throw to me, Jay Leno,
In the news, all they do, is say I’m replacing you,
They think I can woo,
Leno: So the network said, “Here’s an idea,”
Pack your bags, take a hike, NBC, yeaaa!
Fallon: Tonight, Tonight,
Who’s gonna host Tonight?
Is it gonna be Jimmy or Jay?
Where will they tape Tonight?
In New York? Will it stay in L.A.?
Leno: Tonight, Tonight,
My ratings were all right,
Twenty years and I’m still in first place.
I’ve got Fox on the line,
Or maybe I could take over for Dave!
Leno & Fallon: Tonight, Tonight,
Why do they say we fight?
I like you, you like me, we’re okay.
Who cares who hosts Tonight?
People just watch online the next day!
As we previously reported, Fallon, 38, is expected to overtake Leno, 62, for the throne in the fall of 2014, and NBC will relocate the show back to New York to accompany him. The network covets Fallon's youth and finger on the pulse of pop culture, as he's a master of new media, generating buzz with viral bits on YouTube, and interacting with fans on Twitter.
Watch the video on RadarOnline.com