If you saw film crews roaming the Harvard campus freshman week, you were not imagining things. While the route from a prestigious Eastern prep school to Harvard may not be the most sensational of subjects, it is the focus of a new Hollywood comedy in the works.

The crews were filming shots of Harvard's exterior that will probably be included in an upcoming movie titled "Class" and starring Jacqueline Bisset and Cliff Robertson, among others. Orion Pictures plans to release the picture this July.

Not Shot Here

Although the movie follows two prep school seniors to Cambridge, many of the scenes depicting Harvard were actually shot this fall at Northwestern University in Evanston, III.

The Northwestern scenes were needed because Harvard does not allow filming of the interiors of its buildings, explained David Greenwalt, co-author of the film.

The college scenes combine Harvard's exterior with the Northwestern buildings and may eventually be edited out in the final version. Greenwalt added.

The scenes were shot at Northwestern because it was expensive to fly film crews to Cambridge from the Orion studio in Chicago, Greenwalt added.

Film producers said the film is appearing now because of "a general interest in prep schools," not because of any particular public demand for movies about prep school and college. "It didn't come out because of the 'Preppie Handbook,'" said Cathleen Summers, the film's executive producer.

The last film made about Harvard. "A Small Circle of Friends," was filmed on campus and was not commercially successful after its 1980 release.

Two Preppies

The movie describes the friendship, sex lives and college admission struggles of two preppies one a rich Easterner who is sure of a Harvard future and the other a lower-middle class student who cheats on his aptitude tests, Greenwalt said.

Bisset plays a rich older woman who becomes involved in a wild affair with the second student, said Nina Tenn, a spokesman for Orion.

The film is directed by Lewis J. Carline and produced by Martin Ransohoff. Robertson plays the rich Easterner's father; in addition, the film stars Robert Lowe and Andrew McCarthy as the prep school students.