How is Alex D. Linz approaching life as the next Macauley Culkin? Extracting the answer from the 8-year-old turns out to be as hard as pulling teeth. In fact, it may even be harder.

Three scheduled interviews with Linz for this story were canceled when a dental emergency of to-pull-or-not-to-pull consequences presented itself on the Chicago set of “Home Alone 3.” With a month of on-location filming re-maining, Linz showed up for work one morning with a very loose front tooth.

The filmmakers opted not to work Linz’s soon-to-be-spacious smile into the plot. Instead, they sought a dentist to convert his tooth into a temporary prosthetic device, called a flipper. When they couldn’t find a dentist to do the job in Chicago, Linz was flown back to Hollywood for the procedure. But because Linz’s mother had come down with the flu, the little actor was sent, well, home alone.

Such are the seemingly fateful energies propelling the sudden career of the precocious third-grader.

“The moment I saw Alex I knew he was the one for the ‘Home Alone’ part,” says Billy Hopkins, the casting direc-tor who oversaw a highly publicized national search to fill the role. “His talents are so special and obvious. There are so many professional wind-up kids who all sound the same. They can ‘be happy’ or ‘be sad’ but they can’t seem to ‘be real.’”

Significantly, it was Hopkins who first discovered Culkin while casting a production of Keith Reddin’s play, “The Big Squirrel,” and it is Hopkins who cast him in his first screen role in “Uncle Buck.”

“When I saw Alex for the first time I got the same feeling as when I first saw Mac — you know, the feeling that you just KNOW,” Hopkins recounts. “I wasn’t looking for a carbon copy of Mac but I was looking for some of the same qualities that made Mac work in the (“Home Alone”) role — that naturalness.”

Hopkins wasn’t the first to be impressed by Linz. Stardom seems to have been stalking the boy since he was born.

“Alex was always the kind of kid who liked to entertain himself — to sing a song, pretend he was playing guitar, that kind of thing,” says his mother, Deborah Baltaxe. “Alex would do it very spontaneously, when we were at the mall or something, and people would notice. Strangers would approach me and say, ‘Here’s my card, I’m an agent, call me.’ It kept happening, but I did nothing for about a year.”

Baltaxe, a law school graduate, and her husband, Dan Linz, a psychology professor at the University of California at Santa Barbara, never intended for their son to get any closer to stardom than sitting in front of the television.

“But one day Alex was watching a commercial that showed kids acting, playing with toys,” Baltaxe says. “He told me ‘Mommy, I’d like to do that.’ So I called someone and asked, ‘How does this work?’ “

Very quickly, thank you.

Linz was five years old when he completed his first screen test and he was soon cast in a J.C. Penney commercial. More than two dozen other commercials have followed, including a recurring appearance as the “McDonald’s Kid.” Meanwhile, Linz won roles in a smattering of TV shows, including “Cybill,” “Lois & Clark: The New Ad-ventures of Superman,” “Step by Step,” and the telefilm “The Uninvited.” His first motion picture was “The Cable Guy” with Jim Carrey, followed by his breakthrough role in “One Fine Day,” in which Linz played third banana to Michelle Pfeiffer and George Clooney.

“Things have really snowballed,” says Baltaxe. “It’s all become much bigger than we ever anticipated.”

Baltaxe has watched very closely for signs that this new life may have been robbing Alex of a healthy childhood. She is constantly with him on the “Home Alone 3″ set during a filming schedule that goes six days a week, 8 1/2 hours a day.

“You’d be negligent if you weren’t always asking yourself, ‘Is this the right thing for my child?’ I ask myself every-day,” she says. “I ask Alex, too, ‘Is this OK? Are you having a good time?’ But no matter what he says, if I notice any behavior changes or anything that looks like a problem, I definitely find out what’s going on.”

Baltaxe is convinced her son is thriving in this environment.

“Mostly, Alex looks at it as fun. He loves the process, both acting and learning how a movie is made,” she says. “Once in a while he makes a suggestion to a director, which is really funny. He doesn’t ever complain, which is amazing because he has worked very hard. There have only been two days where he’s said, ‘I’m tired. I don’t want to go.’ “

Several people equate Linz’s strong personality with his success as an actor.

“Alex is so delicious it’s astonishing,” says Linda Obst, producer of “One Fine Day.” “He is a complete natural. He’s not an actor kid, he’s a real kid, and that’s so rare for those of us who work often with child actors.”

Those qualities will translate “Home Alone 3″ into Linz’s movie, says Ricardo Mestres, co-producer of the “Home Alone” series. So will the plot.

“This new movie is not a derivation, it is a whole new direction,” says Mestres. “Along with Alex, we have a new family in a new city with a new plot and new villains.”

Instead of the two bumbling burglars who were undermined by Culkin in the first two “Home Alone” installments, Linz will be faced with a quartet of international thieves who are in desperate search of a computer chip containing top-secret U.S. defense plans . The chip has been hidden inside a toy car.

Culkin was never considered for the role, although not because of any shortcoming — or the much-publicized controversy regarding his parents’ struggle to control his career.

“Obviously, at sixteen Macauley is too old to play the role, which depends on the peril of a young child left home alone,” says Mestres. “The peril of a 16-year-old home alone is that he will throw a party and tear the house down. That movie has already been made. It was called ‘Risky Business.’ “

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