To say nothing of being No. 1 in each medium. On the small screen, the baby-faced Thomas plays Tim Allen's middle son, Randy, on the top-rated ABC sitcom Home Improvement. On the big screen, his is the voice of the young lion Simba in Walt Disney Pictures' animated box-office smash The Lion King. "I had to kind of go, 'Oops! Time to be Randy'...'Oops! Time to be Simba,' " says Thomas, who for the last two years shuttled between the sets, both on Disney's Burbank lot. "You have to prepare yourself to become this totally different person. I mean, we're not lions, right?"
No, but sometimes lions are us. "Simba's like me," says Thomas, who didn't even need to alter his normal voice for the role. "Real curious, fun-loving, always getting into mischief."
Those were exactly the traits that Lion King producer Don Hahn wanted. "We had this role for a scrappy young kid to play Simba, and we looked at dozens and dozens of actors before choosing Jonathan," Hahn says. "But we saw him on Home Improvement and just thought his voice was right. It gives him a very distinctive character."
Not that Thomas's hour-long sessions in front of a microphone at the Disney recording studio were a stroll through the safari park. "We darn near beat him up when we were recording," says Hahn. "We had to make it sound like he was being flung down chutes in the elephant graveyard and being chased by wildebeests. So we would rough him up at the microphone and try to make him out of breath."
Thomas already had got on-the-lot training for this knockabout action—as actress Patricia Richardson, who plays Thomas's mother on Home Improvement, can attest. "There's a lot of boy humor going down on our set that I try to stay away from," she says, mentioning flying footballs and other projectiles. "I mean it's a dangerous set to walk across."
Most of the time, though, Thomas's friskiness is dampened by a killer schedule. His 9 ½-hour days on the Improvement set include a full day's schoolwork (when the show is on hiatus, he's a straight-A student at a Los Angeles public school), and his summer vacation is being spent in Vancouver, B.C., with Chevy Chase and Farrah Fawcett on the set of Disney's Man 2 Man. That leaves precious little time for his favorite recreational activities, fishing and collecting sports cards. (And no time at all, yet, for a girlfriend.) "You have school, friends, learning your lines and making sure your performance is up to speed," says Thomas, miming a juggler. "I can't tell you how many shows I've done with full-blown migraine headaches."
That Thomas can stand and deliver with such precocity is a trait his mother says was evident "even when he was 18 months old. He seemed older than his age, and he was really outgoing. Everyone kept saying, 'Wow! Why don't you get him on television.' " Born in Bethlehem, Pa., Jonathan was 4 ½ when he moved to Sacramento with Claudine, his father, Stephen Weiss, an industrial sales manager (who was divorced from Claudine in 1991), and brother Joel, now 16. After beginning in modeling, Thomas landed a Burger King commercial in L.A. when he was 8 and found the prospect of a career in showbiz "pretty cool. So I asked my mom and got signed up for acting lessons. I just thought the whole idea of being on TV, being recognized and having a good time was interesting."
Alas, despite his lion's share of success, Thomas is not the king of beasts in his schoolyard. "The bigger kids like to give us sixth graders a hard time, trying to put us in trash cans and stuff," he says. Hey, even if you're 12, it's a jungle out there.
MIRO CERNETIG in Vancouver