'Tonight Show' host Jay Leno joined forces with his possible replacement -- 'Late Night' host Jimmy Fallon -- for a parody of 'Tonight' from 'West Side Story.'

Aired between the two programs on Monday, April 1, the bit started with Jay ending his program and placing a call to Fallon, two minutes before he's set to go on.

The two discuss how, no matter what happens, they will still be friends, before Jimmy bursts into song, singing: "Tonight,Tonight, who's gonna host Tonight / Is it gonna be Jimmy or Jay / Tonight,Tonight, where will they tape Tonight / In New York or will it stay in L.A.?"

Jay follows suit, replying, "Tonight,Tonight, my ratings were all right / 20 years still in first place / Tonight,Tonight, I've got Fox on the line / Or maybe I could take over for Dave."

That last bit is a sly nod to the possibility of Leno moving over to FOX, which doesn't have its own late night program, or even taking David Letterman's seat at CBS if he opts to retire next year.

Leno and Fallon have been in the news regularly ever since news leaked that NBC was planning to replace Jay with Jimmy. It's good to know they're taking it in stride -- at least with each other.

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