Tonight on Letterman: H-E-E-E-E-E-E-R-E's JOHNNY!

Former late-night titan JOHNNY CARSON, 79, left, retired from his paying gig at NBC's Tonight Show in 1992, but he's now spinning jokes for free. Carson, who likes to riff on current events, writes one-liners and slips them to DAVID LETTERMAN, 57, right, who uses the material from time to time in his Late Show monologues. CBS executive Peter Lassally, a former producer of both the Carson and Letterman shows, told Reuters that Carson "gets a big kick out of that," and has long considered Letterman, not Jay Leno, his rightful heir. Looks like Leno will have to keep writing his own jokes.