The 36-year-old rock 'n' roll kid counts off, tanned head bobbing. The band instantly locks into the "Late Night" theme, a loungy jazz-funker that makes you want to stomp holes in the rug when you're listening live. The studio audience is primed and applauding before prompter Bill Wendell can even raise his arms, and by the time David Letterman saunters on stage the band is playing as if it's the last song it'll ever do.

"Ladies and gentlemen," Letterman intones with mock grandiloquence, "the greatest musical director in the English language, Mister Paulie Shaffer." And as the audience cheers, the cameras switch to the familiar cherubic face, grinning like a gerbil that just ate all the Valium.

"Hi, Dave, how are ya?" comes the trademark nasal reply, gently mocking the laid-back slick-shtick of greasy smoothies from Wayne Newton to Jerry Lewis. It's show biz time, babe, and Shaffer is in his element, playing his version of Doc Severinsen to Letterman's Johnny, the funnest job on the hippest show on TV.

"He's definitely hip," says one tenacious viewer of the show, which recently clocked its 700th night, "because he's not hip."

We're talking about a short, duck-footed, kinda balding guy who wears tinted glasses, dress slacks and Hawaiian shirts, a graduate of the original "Saturday Night Live" and keyboard player of New York's hottest session band, a deadpan jester given to words like "swingin'," "a gas," "us kids" and "this cat" -- a revisionist Esperanto derived from television repeats, Las Vegas glitz, the Rat Pack and rock 'n' roll.

It's a language completely understood by his confre res and the whole postwar generation familiar with all things video and vinyl. But for die-hard "Late Night" fans who have watched the show since its 1982 inception, there is an unmistakable warmth behind those hokey tinted glasses. You may laugh at Letterman's haut sarcasm, but you want to have a pizza and beer with Paulie.

"Hey Paulie!" a stranger hails across Broadway.

"I watch your show every night," says an admirer, spitting beery enthusiasm into his ear at the Hard Rock Cafe, "and it's your show."

"When do you tango?" comes a slinkier, female greeting.

"I grew up feeling that to be hip was really the greatest thing in the world," Shaffer says -- sans smirk. "However, in my quest for ultimate hipness, I realized that when you're not hip, it's really the hippest thing. That's what I try to do, remember how unhip I am."

Paul Shaffer is a Manhattanite with a Type A schedule, and you have to catch him on the fly. Sunday night he's hosting his radio show. Monday he has appointments, that night it's "Late Night" -- natch -- and a three-hour band rehearsal. "There's always something going on," he says late-late Monday night in a noisy SoHo bar.

He seems a little bushed, but contentedly so. He's also quieter, shyer than the television Shaffer, fidgeting like a schoolboy asked to recite the pluperfect when asked about himself.

The guy we see on the tube, he says between mouthfuls of endive, "is basically just me, a little bit more exaggerated . . . And certainly my fascination with parodying the old-fashioned type of performer, who I hate and love at the same time, has caused -- maybe some of their style has rubbed off on me. Although I'm always at least half-joking when I speak in those terms."

While his "Late Night" life seems one prolonged romp-video, there's still a lot of romping to do. That was Shaffer as the phony-toned rock promoter Artie Fufkin in the brilliant rockumentary spoof "This Is Spinal Tap." That's Shaffer performing an updated "Rock Around the Clock" for the sound track of the upcoming "The Karate Kid II." That was Shaffer lolling all over pop princess Whitney Houston on a recent "Friday Night Videos" and jetting to L.A. to shoot a segment for HBO's "Comic Relief" and zipping up to New Jersey's Meadowlands to cop a quick backstage interview with rock star Paul Rodgers for his monthly "Live From the Hard Rock Cafe" radio rap show.

Not bad for a kid raised in the mill town of Thunder Bay, Ontario, who figured he'd end up "maybe a lawyer."

"I was way up north in Canada," he says in matter-of-fact mono. "There was nothing happening up there, nothing hip at all."

Until he heard Gene McDaniels' "A Hundred Pounds of Clay," circa 1961. "I found I could play it on the piano." From then on he listened incessantly to this thing called rock 'n' roll, tuning in to American stations after dark.

"These songs became a spiritual pipeline down to New York. There was a whole world of people living glamorous lives and I could listen to the records and, you know, get inside there with them. Since coming to New York it was quite important to me to seek out, meet and work with these people who made the records that I grew up with."

Which is precisely what he's done. Since settling in New York in the mid-'70s he's played with Chuck Berry and Jimmy Cliff, Jerry Lee Lewis and Diana Ross, Burt Bacharach and Yoko Ono, Dizzy Gillespie ("he was the toughest") and Eddie Van Halen ("unbelievable guitarist") -- virtually all of his music heroes except Phil Spector, that deficiency just a matter of time, he asserts.

Jamming with James Brown recently, he says, was "the most exciting event in my life."

The Rock 'n' Roll Dolce Vita -- it's all he ever wanted.

"Hey, we did Eddie Layton!" Shaffer says with the glee of an autograph hound after the Yankee Stadium organist's recent sit-in with the "Late Night" band.

The band members are copping quick beers before a studio rehearsal, and Shaffer is rifling through a bag full of classic rock records he wants them to hear. Anton Fig, the new drummer, suggests a cover of the O'Jays' "For the Love of Money."

"Yeah, 'Money'!" Shaffer says. "That's a great song." He hums a few notes. "Yeah, we could do 'Money.' " And with that the band leaves en masse in search of an O'Jays album.

"So we did Eddie Layton!" Shaffer says outside the Rockefeller building.

"We did Eddie Layton," he says again in a cab to the studio after they've found the album in question.

Again in an elevator.

Again out on the street.

"You'll be going out to dinner with him," says Jim Pettigrew, Shaffer's Hard Rock musical coordinator, "and all of a sudden a song will come on and he'll start banging on the table and he'll go nuts. And of course it'll be something obscure. He's like a little kid -- it's great to see someone not lose that."

At rehearsal that night Shaffer is in his element, one hand on the keyboards, his eyes and ears on the band. The familiar "Late Night" grin returns as he plays and replays classics by the Rolling Stones and Cream -- and, of course, "For the Love of Money." He is the most benevolent of music leaders as he tells guitarist Sid McGinnis to come in earlier, tells drummer Fig to put "more big band" feel into it, asks stand-in bass player Neil Jason not to "swing so much."

"I have a band that's not only a rock 'n' roll band -- we have the versatility to cover anything," he says. "One night we might play with an opera singer, another night we may have to play jazz. We enjoy playing together and we play the hell out of the songs we do. I only play the favorite songs of the guys in the band, and I get guys who give me 100 percent."

Shaffer's music buttresses the show with "a real discernible energy," says Letterman, puffing at a cigar in the makeup room. "For me that's a real important element when I walk into the studio. It feels like there's a little buzz, and I feel like Paul's largely responsible for that."

The band is known for a certain musical irreverence. When Letterman talks at length about the cosmic significance of a panel of mounted meteorites, for instance, Shaffer suddenly pumps out a bowling alley theme.

"David is out there by himself," he says. "I try and support him. And my hands aren't tied, either."

"On the shortest notice Shaffer will create a spontaneous composition on any subject," says "Late Night" head writer Steve O'Donnell. "I mean, we've had short musical tributes to [baseball player] Harmon Killebrew and to Arnie Barnes, our correspondent in Omaha, Nebraska. Sometimes we'll show a dumb advertisement and Paul will create a spontaneous song in salute to freezer bags for meat. He just writes really fast with a fully formed little gem of a song."

"You know, when the audience is wild when Letterman comes in," says Victoria Berdy, a percussion session player and old friend of Shaffer's, "that's not for Letterman. They're really screaming for the band."

At the close of rehearsal, Shaffer sits back on a sofa and says, "I can't believe we did Eddie Layton."

"Get smashed!" Shaffer vamps as the schmaltzy host of the Hard Rock show. "Order all the champagne you want and put it on my tab. It's always a party, it's always a gas. And you never know what kind of swinging rock stars are going to come by."

His emcee patois is unshakable, say associates. "He loves a specific kind of show business," Letterman says. "The Frank Sinatra, Las Vegas kind of cuff links and finger-snapping kind of show business. He's a real student of it, and I think he would also like to participate in it a little, so that the line is not clearly drawn to objective observation. And it may not be clearly drawn in his own mind, because I think he will admit to going back and forth across the line."

"I can't completely clear up the mystery" about Shaffer, says O'Donnell, "because he is what he appears . . .

"My dad's a retired welder in Cleveland. He's always saying, 'That Paul Shaffer, he seems like such a phony.' I have to go, 'Well, Dad, he is and he isn't.' It's yes, it's all a joke, and yet it isn't a joke. He's trying to draw the fun out of the kind of malarkey that is offered seriously on most other television programs, the kind of gushing and flattery and excitement that people attach to the activities and personalities of stars. His wallowing in it is as much a pointing to its absurdities as it is a partaking of it."

Shaffer might be doing Jerry Lewis imitations in some back office in Canada if he hadn't tried out at a "Godspell" piano audition. For the 22-year-old University of Toronto sociology graduate, that local production -- featuring celebs-to-be Gilda Radner, Eugene Levy and Martin Short -- was an entree to the network of comedians and musicians that would form "Saturday Night Live" and "SCTV."

In the early 1970s he moved to New York and was signed up by Canadian buddy Howard Shore and producer Lorne Michaels as the pianist for "SNL." He collaborated on music and comedy writing, including the celebrated Bill Murray lounge lizard pieces -- which Shaffer acknowledges as a strong influence on his own comic persona. In Murray's rendition of the "Star Wars" theme, Shaffer's donation was: "And hey, how about that nutty 'Star Wars' bar!"

He also made some forays on screen. His first role was as Igor in a musical number about Frankenstein. You may also remember him as a multinerdy Don Kirshner, introducing the first appearance of the Blues Brothers.

"SNL" was five years of fun and games and ego battles. At the fun end was the Sammy Davis Club, an unofficial huddle organized by Shaffer, Bob Tischler and Brian Doyle-Murray. "I became fascinated by this show," he says, "and we started a sort of a regular Sunday night gathering. We would watch very carefully the 'Sammy and Company' show."

At the other end was the off-camera clashing among the Not Ready for Prime Time Players. When John Belushi wanted Shaffer to play exclusively for the Blues Brothers and Lorne Michaels wanted him for the simultaneous "Gilda Live" performance, Shaffer "was caught in a sort of double bind." Belushi threatened and Michaels implored. Somehow Shaffer finessed appearances in both projects with his body intact. "Everything about him is benign," says Michaels, by way of explanation.

"It was great to be around while it was happening," Shaffer says of "Saturday Night Live." "But by the same token, I was pretty far from the center of activity. I'm happier now because I'm closer to the action on the Letterman show."

"The action" means just about anything he feels like. If he wants to scream out "Ray Charles!" for no apparent reason, he can -- and has. Let Paulie be Paulie, is Letterman's policy. But at the apparent crest of his comedic career, Shaffer is consciously cutting back on the show biz stuff. "It's getting old," he says.

And worse, he worries -- tongue in cheek -- whether his hipness factor may be peaking. On his radio show, Shaffer recently asked guest Andy Warhol "how a kid like me could be as hip as him when I grew up. He said, 'You're already hip' on the Letterman show. But now that he's finished talking to us, we're not hip anymore. I've had my 15 minutes."

The attendant benefits of "Late Night" fame have certainly made Shaffer's personal life better. "I certainly can get a date now," he says, although he only recently ended a steady relationship of 6 1/2 years. "I'm trying to stay single," he states.

Professionally, he is content to stay where he is. But given television's propensity for purging the qualitative, he will be happy "just to be part of something else." He balks at the obvious move -- toward a solo recording career. "I don't know," he says. "I'm afraid. I'm afraid to commit to it. Always gotta have this comedy thing to say to the world -- 'Yeah, I do music, but it's only one of the things I do.' "

As a matter of fact, he has This Idea:

"Maybe it's not a movie, but more like a pay TV thing. 'Viva Chez Vegas' would be the title -- the story about me and my struggle to find the true meaning of life. I journey a sort of a Homeric odyssey through the underbelly of Vegas nightlife. And I come out on the other end having, you know, a peaceful soul."