You figure you're supposed to recognize him, the muscle man with the white hair rising from his forehead like tufts of albino wire, his face contorted into a cartoon-sized grimace as he pummels the air and shouts from your television set in an unmodulated, nearly unintelligible Australian accent about -- what's that? Oh, yes, batteries.

He must be a rock star, you think, or a professional wrestler, or some other cult figure intended to appeal to people younger, hipper or louder than yourself.

But you are wrong. He is Jacko, an Australian-rules football player also known as Mark Alexander Jackson, and until last month when he and his Energizer commercials smashed their way onto the television screens of this country, you had probably never seen him before. But now, it seems, almost everyone with a TV has been assaulted by the Popeye-pointy face shouting "WHAT'S THE LONGEST LASTING BATTERY YOU CAN BUY? ... NEW ENERGIZA'! IT'LL SAPRIZE YA'!"

Among viewers, the reaction seems to fall into two categories: (a) "I love him" and (b) "I hate him."

Stuffed into an Energizer jacket and concerned with a lunch-time cheeseburger, Jacko actually borders on the demure. "Sometimes I'm really vibey -- that means really up -- and sometimes I'm really quiet," he explains. "It just depends when you get me."

Now, he is definitely unvibey. A relaxed former bricklayer and lifeguard who's just finished a nap in his stretch limo, he tells long, loving tales about the beauties of Australia's beaches and the many creatures native to its waters that can maim, injure and kill unsuspecting swimmers. He hoists no huge batteries over his head, does not emit his trademark cry of "OY!" (rough translation: "HEY!"), but does insist upon opening up a reporter's tape recorder to check on the power source. Energizers! He grins, instantly transforming his face into a gleeful, contorted mask, more reminiscent of an ancient man than the 28-year-old he is.

"A lot of people mistake me for being 80 years old," he says. "I think I've got a baby face. A baby with a nouveau haircut." He pats the white spikes and smiles, pleased with the bleached hair and the ritzy adjective. "Nouveau," he repeats, savoring it all.

The nouveau hair is something new, but what he calls "the Jacko mystique" has taken years of perfecting.

"In Australia, I'm well known in my own right," he says, his voice defensively crisp around the edges.

Down Under, everyone knows he is a star of Australian football, a fierce game that falls somewhere between American football, English rugby and general mayhem. They know him as the player who likes jumping into the crowd and doing back flips and running through the other team's banner and generally "giving the people what they really want." They've heard about the upcoming film, "Jacko: The Mad Movie." ("It's loosely based on reality," he says. "It's about a bloke who comes down from the bush with his mate and his mate's name is Underpants Harry.") They remember the four professional heavyweight boxing matches, the manic appearances on variety shows, the bestselling autobiography "Jacko," the antidrug and antismoking lectures, the single on the Raw Prawn label ("I'm an Individual" with the flip side "Our Relationship Is Giving Me the Creeps").

"We were looking for a product I'd fit in with," Jacko says, "because the character Jacko is really energetic and powerful. It was no good if I was going to endorse a product that was airy-fairy."

And so when Eveready's Australian subsidiary decided two years ago to plug its Energizer batteries by hiring Jacko to shout "OY!", it made sense. For Australia.

Energizer sales went up 40 percent. Jacko was then loosed on New Zealand, where his face and physique were unknown, and the same thing happened. And now he's here.

"I think of myself as a walking billboard," he says. "People who see me can immediately recognize I'm on that commercial."

Especially when aided by the Energizer jacket, a 21-city publicity tour, Jacko masks distributed at a New York press launch and Jacko's own determination to drop Energizerisms into conversations whenever possible. "He really embraced this product and lives it," says Eveready spokeswoman Harriet Blickenstaff.

Stranger at a restaurant: "I heard you on the radio this morning. Got any energy left?"

Jacko: "I always do! Jacko lasts longer than all the rest! Oy!"

Blickenstaff calls Jacko "a phenomenon. He's very fresh and new and he's very breakthrough. If you look at commercials on TV, to use his own quote, he sort of jumps out of the TV set, grabs you by the throat and jumps back in. He really cuts above the clutter."

Perhaps it is history's most honest commercial, blaring its intent ("Remember the name of our product -- or else!") with no false subtlety or seductive images. Or perhaps it is history's most sophisticated commercial, cynically playing on viewer curiosity and media willingness to expend paper and air time satisfying viewer curiosity with articles like this one.

Jacko's not one to ponder at great length the nature of the commercial that he hopes will make him an American celebrity, although he does bristle when the ad is called "aggressive."

"It's a high-energy type thing. It's not meant to be aggressive. At the same time, it's got to stick out. I think using the word aggressive is too strong."

Blickenstaff aims toward moderation on the subject as well.

"I think that's true with any celebrity, there are admirers and detractors," she says. "I think if you came up with a person everybody liked, you wouldn't be very breakthrough -- it would be like oatmeal with brown sugar."

And no matter what, Jacko is certainly not soothing breakfast food. "High energy" is a way of life for him, sort of a philosophy. But don't confuse high energy with arrogance. Success, he says, "hasn't changed me. It hasn't gone to my head. I don't get carried away. The good thing is, with me, what you see is what you get. No frills, no spills. You can't do better than your best, although lots of people try."