Charlie's Georgetown, the elegant Northwest nightspot devoted to the art of jazz, made room Monday night for the art of theater.

Fine Line Actor's Theatre, an offshoot of Earth Onion Women's Theatre, rented Charlie's for a benefit dinner and show featuring jazz singer Ethel Ennis. A native of Baltimore, Ennis has an international reputation that was enough to make sponsors peel off $25 to $50 for the night.

But it was a sneak preview of "Getting Out" and a skit from "The Last of the Red-Hot Lovers" that gave all present the satisfaction of having spent their money well. Most of the proceeds from the evening will help Fine Line put this season's productions on stage.

Marla Orchen and Leonard Martinoli, with the help of a bottle of Scotch and two glasses set cozily at an impromptu bar, turned the Charlie's stage into a New York apartment where "Barney," a real square, has only two hours in which to seduce "Michelle," a zingy aspiring actress. Though Orchen and Martinoli only gave a glimpse of the hilarious antics and conversation neil Simon wrote into "The Last of the Red-Hot Lovers," their bit left most of the audience wanting more.

The play is not on Fine Line's season schedule. It was a project of one of Fine Line's ongoing professional acting workshops and was sneaked into the sneak preview. But director Judith LeGrand hinted that because of the play's popularity Monday night, it just may be added.

Fine Line does promise "Getting Out," Marsha Norman's sobering drama about women in prison. Susan Goldstein, playing an ex-convict, paced in front of the stage as Judith Miller, playing a younger version of the same character, paced onstage in the opposite direction.

The effect was powerful, particularly when Goldstein crumbled from the haunting memories of here attempted suicide while Miller was onstage trying to commit the act. "Getting Out" will be Fine Line's first production this season, beginning Feb. 26 and continuing at D.C. Space for seven performances.

Some of Washington's top supporters of the arts were at Monday's benefit, including City Councilwoman Hilda Mason, National Theatre's Kathy Barry and Arena Stage's Thomas Fichandler. Mark Hammer of Arena Stage introduced the benefit program.

Fine Line has been in residence at the Hanover Arts Project, 57 N St. NW, since last May but, because of zoning problems, has not yet performed in the space available there. LeGrand says she hopes to bring "Getting Out" to the site before its run ends and to continue there for the rest of the season.

Fine Line's tentative season schedule runs like this: Noel Coward's "Private Lives" in April followed by two short Tennessee Williams plays, "Gnadiges Fraulein" and "Two Character Play."

The final production will be either Lillian Hellman's "The Children's Hour" or Arthur Miller's "The Crucible." Guests at Monday's benefit were asked to help choose between the two, but it's not too late to cast more votes. To do so, or for more information on Fine Line's workshops and season tickets, contact LeGrand or Miller at 462-6396.