LOS ANGELES -- Those who forgot about Veronica Hamel the moment Megan Gallagher first appeared on "Hill Street Blues," and feel a tingle whenever she launches into another string of double-entendres with Dabney Coleman on "The 'Slap' Maxwell Story" are entitled to know something about the woman of their dreams.

I am obliged to reveal that Megan Gallagher was the kind of girl so beautiful and yet so self-confident and independent and driven that, despite several invitations to the Wyomissing (Pa.) High School prom from moonstruck suitors, she passed it up for one more night of rehearsal at the local theater. She was director, set designer, drama coach and star, the mainstay of the high-school drama program and a girl who knew her own mind.

She was a serious person, a little ahead of her age group. At 27, she still seems that way.

It requires some readjustment to meet Gallagher for lunch after watching the actress in her two principal television roles to date: Tina Russo on the defunct "Hill Street" and (on Wednesday nights at 9:30 on ABC) as Judy, Slap Maxwell's girlfriend. Her characters seem to wear a great deal of makeup. She does not. The come-on attire of the undercover cop or the sassy secretary has given way to the baggy dress and sweater of the undergraduate at the Juilliard School, which she once was.

She is spirited and candid, like Slap's girl, but the hard edge of the big-city cynic that outlines her television persona fades in the restaurant, replaced by a wide-eyed intellectual, full of talk of books and philosophers. Her friends in New York talk about her eagerness to steer their cultural lives, recommending the new exhibit at the Guggenheim they must see immediately.

She exudes an actress' delight in doing so well by characters at such distance from herself, but she writes off her remarkable early success as mostly luck.

Her parents -- who met while performing a play at Catholic University -- think differently. From the moment their fifth child began to act in her early teens, they saw an unusual, precocious talent -- perhaps just the thing for a still unspoiled television show whose admirers worry that popular taste and network finances could strangle it in the cradle.

Gallagher says she loves "Slap" and its creator and producer, Jay Tarses: "I think it's making television history ... There are no simple relationships in this show. Jay seems determined to break formula, and that's extraordinary because television has always been based on money-making ideas. It's a factory and that's not what this is."

The show exploits a Gallagher strength, an uncommon grasp of the fine line between drama and comedy that impressed some of her earliest directors. New York producer-director Kent Paul, who later became a close friend, cast her in Strindberg's "Miss Julie" off-Broadway after seeing her captivate a New Haven audience as the inge'nue in a period piece, Paul Osborn's 1936 play "Oliver! Oliver!"

"She had this very natural, easy comedic touch while making you feel very deeply about the character," Paul says.

Gallagher is likely to return to the stage, her friends and family insist. But television salaries do allow certain luxuries, like shedding the clunkish brown Honda one of her brothers sold her for $5,000 when she first came to California.

Her early television roles established a public image with which she was not enthralled. She played a prostitute in the TV movie "Sins of the Past." And then came Tina Russo. "If somebody recognizes me, they usually say, 'Oh, yeah, you were that loose cop on "Hill Street." ' "

Gallagher was from John Updike country, those rusting eastern Pennsylvania towns around Reading. Tarses had once worked in a cork company in Lancaster, and had toured the area as a struggling stand-up comic. She and Tarses clicked right from the beginning, she says. "Jay and I have pretty much the same sense of humor. We just talked and kidded around and then I read and it was all very, very good. It felt just perfect."

Her first "Slap" audition took place on the 26th floor of a New York office building; she was doing Shaw's "Major Barbara" in Baltimore and could only see Tarses on a Thursday morning. It felt so comfortable that she was not as prepared as she might have been for the more difficult follow-up. Tarses liked her, but she had to meet the network.

That audition before ABC executives, without Tarses present, was a painful introduction to the level of network humor. Tarses had grown tired of formula jokes and canned laughter and produced a script that demanded an appreciation of subtlety on the part of both actors and audience. For the ABC executives, Gallagher gave the words a natural reading, as Tarses had asked, and, she says, her listeners did not get it.

"Uh ... could you, ah ... you know ..." she says one asked. Biting her tongue, choosing to accept this as an acting challenge, Gallagher landed hard on a few delicate punch lines and got a response, but she did not feel so good anymore.

Tarses came to the rescue, arranging a Los Angeles meeting with Coleman, the series' star; Bernie Brillstein, the executive producer; and assorted network heavyweights. Gallagher read a bit more, then was asked to leave the room for a few minutes. Tarses soon emerged with a big grin and a handshake. "It's going to be a pleasure," he said.

Tarses was right (she was the first of many actresses, including Catherine Hicks and Patricia Kalember, to try for the role). Gallagher says she enjoys working with Coleman, who is as serious as she is about the job at hand, and often as unpredictable as his character. "He never takes anything for granted in the scene," she said. The legendary Coleman intensity still exists, but much of the even more infamous foul temper seems to have evaporated in the warm breeze of critical acclaim for "Slap."

The mesmerizing Slap-and-Judy dialogues, set pieces that the uninitiated might expect to take hours of rehearsal, are often molded into shape in less than an hour. "It's all there already, right there in the writing," Gallagher said.

Unlike most half-hour television comedies, the show is filmed -- not taped -- and does not use an audience. ABC spokesman William Saul says Tarses thinks of his work as a movie, cut into small pieces. The producer likes the intimacy, the ability to go for tight close-ups. He likes going on location.

That was the way "Hill Street Blues" was done. Gallagher came late to the series, appearing in only the last of "Hill Street's" seven seasons. She began with a three-show guest appearance, as the alluring undercover officer who occasionally crossed the line from investigation to entrapment. The character worked well, but instead of signing her as a regular, MTM company executives asked for three more guest shots.

"I suspect that it had something to do with money," she said. "I said, 'Pick me up or drop me, forget it.' " They picked her up, and she proceeded to learn much on the set about filming a television series produced by perfectionists.

"It was insane. Shots would last forever ... In 'Hill Street' everything is always moving, a swirl of movement all the time, so there were always dolly shots, meaning the camera was always moving and following people. You had to hit your mark within an inch of your life."

In that last "Hill Street" season, she earned $8,500 a week. Her salary on "Slap," she said, is not much more -- spectacular for most actors but below what leading actors in a weekly series generally expect.

Since she was 14, seduced by the stage while watching her mother in local theater, Gallagher has seen little of failure. She and her younger sister Melissa, now appearing in "The Witch of Edmonton" at the Shakespeare Theatre at the Folger in Washington, conquered local theater in Wyomissing, and then attended Juilliard. Their mother Aileen, who raised six children, gave the girls their early direction. Their father Donald, a retired Aamco franchise owner, remembers Megan was "a shining light" in her classes at Juilliard.

She joined the John Houseman Acting Company and then found other acting jobs arriving in relatively rapid succession. She never had to wait on tables or teach school. She had several jobs on stage and television appearances as Benedict Arnold's wife in the "George Washington" mini-series, the lead in a failed pilot, "At Your Service," and a brief appearance as an attorney in the pilot of "L.A. Law."

"Hill Street Blues" followed quickly. The series' writers, seeking to avoid the torpor suffered by most older series, entertained the disturbing notion of turning Gallagher's character into a home-wrecker. They considered a Tina Russo affair with Mick Belker, the Hill's sweet savage, and even, may God forgive them, with Frank Furillo, the show's moral center.

What would have happened to Joyce Davenport, the Veronica Hamel character who had been with Daniel Travanti's Furillo, more or less faithfully, for six years? "Well, who knows?" said Gallagher, smiling wickedly at her questioner's distress. "It would have been a complicated situation. I think it would have been great."

Good sense prevailed. Tina Russo found romance, or something close, with a single policeman. The series died an honorable death from natural causes.

Gallagher said her own personal life includes no serious attachments at the moment. She is a busy woman, just as she was back at Wyomissing High. She runs as often as she can near the ocean in Santa Monica. She reads. She talks on the telephone with friends in New York and dines with friends here.

"I don't know anyone so attractive and successful as Megan who is so open and sincere," said Kent Paul, her friend and former director. "She is exactly what you see."

And she has the good fortune to work for Tarses, the creator of "The Days and Nights of Molly Dodd" and a man known for his skill in writing for female characters. He told Gallagher at the beginning, when they first talked about Judy: "We have many ways we can go with this woman. She is very bright and very sharp and she should be warm, the kind of woman that men die for."

Gallagher grinned. "I'll do my best," she said.