LOS ANGELES Sandra Bullock was visiting Los Angeles when she heard on television that the NBC sitcom "Working Girl" was seeking a new leading lady.

She'd had only a few jobs as a New York-based actress, and was hoping to find regular work here.

"Nancy McKeon had just left the show and I heard on a news show they were looking for someone," Bullock said. "I knew a lot of people who auditioned for it. They were seeing a bunch of people, and my agent sent me. Finally, it got down to about five people, and we went to the network. I think it was my begging that got me the job."

"Working Girl," airing from 7:30 to 8 tonight on WMAQ-Channel, is a spring tryout series based on the hit comedy movie. Melanie Griffith was nominated for an Academy Award for her role as Tess McGill, the character Bullock plays.

Tess is a young secretary from Staten Island who becomes a junior executive in Manhattan, and the series draws on contrasts between her homelife and life in the corporate world.

It also stars George Newbern as a preppie co-worker, Nana Visitor as her hard-driving boss, Tom O'Rourke as a self-made corporate powerhouse, Edye Byrde as the seen-it-all "temp," Anthony Tyler Quinn as a neighborhood Romeo and Judy Prescott as Tess' best friend from childhood.

"Tess is a very stubborn woman, but in a good way," Bullock said. "She's a little more daring in her choices than I am. She's headstrong, but she would not sacrifice her beliefs or her family to get ahead.

"In the first show, she's a secretary again. Then she has to adjust to becoming a junior executive. She doesn't quite fit in and her accent doesn't quite fit in."

The concept has undergone changes to adapt it from a movie to a sitcom, and Tess' character has been altered somewhat, since Melanie Griffith is softer, while Bullock has more of an edge.

Nancy McKeon, formerly of "The Facts of Life," had been set to portray Tess, but left the show because of "creative differences."

Before "Working Girl," Bullock had worked mostly in small films.

"I had a few lines in the ABC movie `The Preppie Murder,' " she said. "I was in `The Bionic Showdown' with Lee Majors and Lindsay Wagner. In New York, I did a lot of small, independent films, the kind you find through the trade papers."

Two of those movies that will be coming out are "Who Shot Patakango," about racial gang violence, and "Religion Inc.," a satire in which she plays a by-the-book lawyer.