It was early yesterday morning and House of Delegates Speaker John Hanson Briscoe was talking on a telephone in his Maryland State House office, trying to finish some pressing business before a busy day of bill signings.

Suddenly, a young, informally dressed man wearing sneakers strode into the office without introduction, casually trod on Briscoe's toe and used a second phone on the speaker's desk to complain to a caterer about Danish pastry.

It was all rather disconcerting. But things are apt to gey disconcerting when Hollywood comes to town. For the past two days, a film crew, a gaggel of Holloywood stars and their director have turned the hallowed State House into the set for a movie called, "The Senator."

"So I walked down the hall to the (House) clerk's office to finish my calls," Brisco said goodnaturedly, "and another guy dressed very casually walks in and said he needs a stool. I said, 'What do you expect me to do, I'm only speaker of the House here.'"

Across the hall from Briscoe's office, a crew was shooting a scene in the marbled House chamber, which was supposed to be the U.S. Senate Chamber. The entire day was devoted to a few minutes of footage showing senators voting on a coal industry bill.

Sprinkled among the fictional U.S. senators were several familiar faces of persons working as extras, including State Sen. John A. Cade, an Anne Arundel County Republican who was cast as a Democrat, and Democratic Secretary of State Fred L. Wineland, who was cast as a Republican.

"After this experience," Cade said jokingly, "I'm going to write a book on what it's like to be a Democrat for $56 a day." The dozens of professional actors who accompanied Cade in the scene earn $56 a day, but no state official will be paid.

Preparing the Maryland House chamber to look like the U.S. Senate required some alterations. Rolls of light blue carpet were stretched over the gold rug and oil paintings of past House speakers were taken off the walls. The clock was frozen at 9:50 a.m.

The normally decorous House lounge became the scene of a slumber party as tired actors stretched out on leather couches while waiting for the next scene. Melvyn Douglas, who stars with Alan Alda and Barbara Harris, sat alone in the darkened room.

The mahogany-paneled Senate lounge was the setting for an earlier scene in which Alda, who plays a rising young senator caught in a conflict between his faimly responsibilities and political career, discusses something weighty with his mentor, played by Douglas.

While the scene was being shot, Bruce Bereano, an aide to the Maryland Senate president, was at his desk in an adjacent office, breathlessly telling a friend about the exciting developments, which he described as "all of the action you see in Hollywood."

Bereano's conversation was picked up by the sensitive equipment on the other side of the wall and broadcast to the technicians. "A guy came in and said, 'Can't you shut up,'" the aide recalled. "You could hear everything I said. It's a good thing it wasn't anything political.