Tiffani-Amber Thiessen; Moving Into Shannen’s Room (August 7 1994)

LOS ANGELES — THIS IS NOT A CINDERELLA story, not by a long shot. When Shannen Doherty, the excessively newsworthy female star of "Beverly Hills 90210," the Fox network's most successful show ever, finally exited that long-running series last season, the last thing its producers wanted was to replace her with an unknown quantity, a tube-struck starlet or a potential loose cannon.

Enter Tiffani-Amber Thiessen, seasoned professional actress. Don't be fooled by her filigreed first name (her parents liked Tiffani; her grandparents liked Amber), her distressed jeans and scuffed Doc Martens or her utterly unlined heart-shaped face.

At age 20 years and 7 months, Ms. Thiessen has probably spent as much time working on television shows as many of her peers have spent watching them. Her career is well into its second decade. She has not been to college or even attended a conventional high school, but has played plenty of high school and college students, appeared in several television and theatrical movies and been a mainstay of a successful sitcom.

"Yes, I've been in this business for a long time," she says matter-of-factly, looking like a Working Woman cover model as she hovers over coffee and a bran muffin at a vegetarian restaurant on the Sunset Strip. "I started very young, and, yes, it's taught me a lot. I understood what fame is, but I also realize that acting is just a job."

Her new job (her first "90210" appearance will be Sept. 7) is to play Valerie Malone, an awestruck transfer student from Minnesota.

As Valerie, Ms. Thiessen will occupy the very same bedroom as did Brenda Walsh — formerly played by Ms. Doherty, who, her co-workers have said, was often late on set. That, combined with her real-life at-large shenanigans, precipitated Brenda's enrollment in acting school, in far-off London, England, several months ago.

"Yes, I move in with the Walshes," Ms. Thiessen said. At first, she adds, Valerie is somewhat disgusted by the fast-lane excesses she's exposed to. "But inside, she really wants to be here and be like everybody else. Meaning, probably, like Brenda."

Producers appreciate a veteran who can step right in and do the job. "Tiffani is wonderful. We've been aware of her for a long time," says Aaron Spelling, the creator of "90210" and Ms. Thiessen's boss. "Don't you get the feeling," he adds, mostly but not altogether humorously, "that she's been here before? In a past life?"

The daughter of a landscape architect and a homemaker, Ms. Thiessen was raised in Long Beach, just south of Los Angeles. She began entering beauty pageants and modeling for catalogues at around age 7, became Miss Junior America and starred in a Barbie commercial. She has appeared in series like "Step by Step," "Charles in Charge" and "The Hogan Family."

Five years ago she won the part of Kelly Kaplowski, a sweet teen-ager, in "Saved by the Bell," the NBC Saturday morning comedy that spent its final season (1993-94) in prime time. On a publicity tour of Europe, where the show was a smash hit, she was pelted with boxes of chocolates thrown by overly affectionate Belgians.

Three years ago she moved to Los Angeles by herself, and now has a steady relationship with the actor Brian Austin Green, who plays the near-dweeb David Silver on "90210."

The show itself, says Mr. Spelling, will probably run "to 2006, when the cast graduates from college." But Ms. Thiessen is not so sure she'll still be there.

"I'm still playing teen-agers," she says. "I don't know if I'll be an adult actor. I don't even know how much longer I want to be in this business. It's going great right now, but who knows? There's so many other things I might want to be doing.

"I definitely do want to go to college for real some day, do it right. But, you know, it's really hard to do it when you're working."