By Nick Charles
April 27, 1998 12:00 PM

Richie and Michelle are missing, and one of NYPD Blue’s finest, actress Andrea Thompson—Det. Jill Kirkendall—is on the case. When last seen, the pair had been seen sitting quietly on the back porch.

“Alec, where are Richie and Michelle?” Thompson asks the prime suspect, her 5-year-old son.

“I don’t know,” he shrugs.

“Didn’t you have them in your room earlier?” she asks. “Do we think maybe they’re still in there?”

Alec thinks for a moment. Maybe this Detective Kirkendall is on to something. He runs to his room and returns with a turtle in each hand: “Here they are, Mom.” Case closed.

Interrogating suspects and solving cases have been the smoky-voiced Thompson’s calling since joining the cast of the top-rated drama last spring. Though her role was first envisioned as an occasional one, Thompson, 38, whose career was unremarkable to that point, sensed it was the part she’d been waiting for. “As soon as I read the script, I said, ‘This one is mine,’ ” she says. She wasn’t the only one who found her a perfect fit. “My immediate reaction was, ‘We gotta grab this one,’ ” says Dennis Franz, who plays Det. Andy Sipowicz. Kim Delaney, Det. Diane Russell on the show, who like Thompson is a single mother raising a son, says, “We really click on the show, and plus, we’ve got the whole ‘mom’ thing going on.”

For Thompson, single motherhood became even more complex a year ago, when Alec was diagnosed with severe asthma, triggered by allergies. “Up until last March, he was the healthiest kid in the world,” says Thompson. Since then she has rushed him to the hospital several times. “Out of the four times that he’s had to go in,” she says, “two of the times he was turning blue as we hit the door.”

But despite Alec’s condition, Thompson does not treat him with kid gloves. “The first thing I do after he gets out of the hospital, as soon as I have the doctor’s clearance,” she says, “is throw him in the swimming pool or wrestle around with him or take him for a bike ride.” The only concession Thompson has made to the illness is to move to an “allergy-friendly” home—it has hardwood floors, rather than carpeting, and other dust-busting touches—in a lush Los Angeles suburb. She also employs a live-in nanny-personal assistant, who shuttles Alec to and from school. Like every single mom, she’s torn by the demands of long work days. “Alec and I have a deal,” she says of one solution. “I have to wake him up and spend 10 minutes with him and watch cartoons before I go to work.”

Growing up, Thompson, to a great degree, looked to her own mother, Mary, a registered nurse, for guidance. When Thompson was 9, Mary and Andrea’s father, Leslie Gerald Thompson, a hotel executive, moved with their four children from Dayton to Melbourne. “A lot of social changes happened throughout the ’60s and ’70s,” says Thompson. “They felt like America was a place they no longer recognized, and that’s what drew them to Australia.” The Australian dream lasted only into the mid-’70s, when Thompson’s parents divorced and Mary moved to Florida with the kids.

Thompson, the oldest, graduated from Vero Beach High School before heading to New York City to pursue acting. Blonde and beautiful, she was sidetracked for a while into modeling, a job she came to hate. “I really wasn’t comfortable with the concept of judging or being judged solely upon one’s physical appearance,” she says. She ended up doing odd jobs: “I waited tables, I bartended, I was a bike messenger for a while, I was a dog walker.” In 1987, while still struggling, she married entertainment agent David Guc; they divorced three years later.

In 1992 she became pregnant with Alec. “It was someone who I had a brief, passionate affair with,” says Thompson, who declines to identify the father. “He doesn’t want any contact, and that’s fine. And if at some point he changes his mind, that’s fine too.” A second attempt at marriage, to actor Jerry Doyle in 1995, ended in a less-than-amicable divorce. “We have no contact whatsoever,” she says.

Thompson doesn’t dwell on those failures. She has signed on to NYPD Blue for three years and spends much of her free time cycling, swimming, lifting weights and watching videos with Alec. “I don’t lie awake at night and say, ‘Oh, I wish I had a man in my life,’ ” says Thompson. “Any time I’ve got I pour into my work and my son.”

Nick Charles

Monica Rizzo in Los Angeles