By Michael A. Lipton
April 07, 1997 12:00 PM

HOWARD STERN, THE SPLEEN-venting radio rabble rooster, remembers the day that Mary McCormack stole his heart. Stern, 43, who plays himself in Private Parts, the film based on his 1993 autobiography, and McCormack, 28, a star of ABC’s Murder One who portrays Alison Stern, the King of All Media’s queen of 18 years, were on a lunch break while filming in Queens, N.Y., last May.

“It was her first day on the set,” says Stern. “One of the other actresses was piling food on her plate. I said to Mary, ‘Look at how gorgeous she is, and she’s eating all that. How does she do it?’ Mary takes her finger and puts it down her throat, like the girl was going to vomit later. I started laughing hysterically. She won me over. I had to do a make-out scene with her.”

Only a month earlier, McCormack had almost gagged after her agent sent her the script for Private Parts. “I was so angry,” she says. “I had the racist-sexist-homophobic Howard Stern stereotype going, and they wanted me to play his wife.” But after reading the script one afternoon in her shabby-chic one-bedroom L.A. apartment, McCormack liked it enough to agree to do a screen test with Stern. In preparation she turned on Stern’s syndicated radio show for the first time. “He was painting some woman’s breast like an Easter egg,” she recalls, “and I just kept laughing.” Meeting Stern, though, proved to be key. “He’s tongue-in-cheek, self-effacing and sweet,” she says. “Once I figured out his act, it became very appealing.”

The attraction was mutual. “I watched Mary’s tape and said, ‘This is Alison,’ ” says Stern. “There were times when I felt like I was married to Mary.” The real Alison insists she wasn’t bothered by their rapport. “I felt a part of it all,” she says. “[Mary] captured the spirit of our relationship, the friendship and humor we share.”

Perhaps that’s because those are also McCormack family values. Growing up in suburban Plainfield, N.J., Mary would entertain her parents—William, 57, an ice-cream store owner, and Norah, 55, a clinical therapist (they divorced in 1990)—sister Bridget, 30, a Yale Law School professor, and brother Will, 23, an actor, by telling jokes at the dinner table. “It was Mary’s job to make everybody laugh, and she was good at it,” says Bridget. “She always said, ‘I’m going to be a movie star.’ ”

In 1991, after graduating from Trinity College, in Hartford, Conn., with a degree in Comparative Arts (painting and creative writing), McCormack, a veteran of regional theater, headed for New York City. “I wasn’t ready to audition. I knew nothing,” says McCormack. “I just bought a book, How to Be a Working Actor, and underlined it.”

That, plus acting classes at the William Esper Studio, eventually paid off. In 1994 she landed a small role in a remake of Miracle on 34th Street and a guest shot on NBC’s Law & Order. Then in early ’95, McCormack got the part of Justine Appleton, the starchy attorney on Murder One. She had brought to the tryout what she admits I was “a pretentious” photo of herself—unsmiling, in a ruffled collar. When executive producer Steven Bochco wouldn’t stop teasing her about it, she says, “I said to him, ‘Shut up, fathead! I still have to audition!’ I think calling him fathead made him realize I should play Appleton.”

To shoot the series, McCormack moved to L.A., leaving behind her boyfriend of three years Barnaby Harris, a stage manager. The two have maintained a commuter romance. Meanwhile her Murder One castmates keep her company. At a local pub where they gather for Friday-night postmortems, “Mary holds court,” says J.C. MacKenzie (who plays lawyer Arnold Spivak). “They love her.”

Last year, McCormack was one of the few to survive a cast shake-up after Murder‘s rocky first season, and though the series’ future looks gloomy (it has been on hiatus since Jan. 23), McCormack remains busy. Back in New York, she’s doing an Off-Broadway dark comedy, My Marriage to Ernest Borgnine, in which she plays, she says, “a crazy, blind 9-year-old.”

It’s only slightly more challenging than her appearance at Private Parts‘ New York premiere in February. “Howard invited me up onstage and in front of, like, 30,000 people asked me how it was to kiss him in the movie,” she recalls. “I stood there for three minutes waving my arms and saying, ‘Uhhhh…ahhhh.’ ” In short, she choked. But at least she didn’t gag.