Jessica Lange and Sam Shepard did what everyone wanted them to do last night. They played Jessica Lange and Sam Shepard.

Noticeably pregnant, Lange was wrapped in black silk, black lace, black velvet, black spike heels and the protective arm of her longtime close friend, Shepard, who seemed to have been surgically attached.

Noticeably himself, Shepard was wrapped in his chiseled face, cowboy boots that never stopped tapping against the floor and a beer bottle that never strayed from his hand.

Lange said almost nothing at all to the audience of 300 guests at the Kennedy Center party in honor of her new movie "Sweet Dreams," a life of country-western singer Patsy Cline. No one seemed to mind.

"I'm a big fan," said a broadly smiling Chris Wallace of NBC to Lange during the prescreening reception.

"Are you happy with the movie?" he asked.

"Yeah," said Lange. "I really like this film."

Then Wallace was swept away into the adoring crowd.

"I must say, to get 200 members of Congress to agree on anything is not an easy accomplishment," said Rep. James Jeffords (R-Vt.), vice-chairman of the Congressional Arts Caucus, as he presented Lange with a Caucus award for her "outstanding contribution to the arts through her portrayal of American women."

"We have had occasions like this before," Jeffords told Lange at the postscreening dinner, "but never have we had so many members of Congress present, and that should show something about how we feel about you."

While the faint notes of a discreet country-western band floated just below the chatter at an after-screening dinner, about 300 members of Congress -- such as Steny Hoyer (D-Md.) and Pat Schroeder (D-Colo.) -- and big-time press -- such as NBC's Roger Mudd and CBS' Lesley Stahl -- smiled warmly at the stars. Lange and Shepard stood off by themselves, greeting only a few and protected by Kennedy Center functionaries, who kept the working press away.

"I hope you enjoyed the film and I'm glad you came," was just about all Lange said after receiving her award.

Shepard was heard telling a guest he had visited the National Gallery earlier in the day.

"That's an amazing place," said the actor and playwright.

The guest agreed heartily.

Everyone seemed eager to agree heartily with anything complimentary to either Shepard or Lange.

"I thought she was great," said Rep. Mickey Leland (D-Tex.) of Lange's performance as Cline, who died in a plane crash more than 20 years ago. But his positive opinion of the movie was, he suggested, somewhat biased: "It was kind of Texasy."

Public relations-types often call the kind of people invited to last night's party "opinion makers," and with "Sweet Dreams" opening in Washington next week, it couldn't hurt for a few local opinions to be sweetened with a little bit of star-gazing.

"From our point of view, it's a grown-up movie," said Michael Fuchs, chairman of Home Box Office, which is "presenting" the movie. "We had a summer of kids movies. It'll be nice to see grown-up people in a theater watching movies."

Or, he might have added, in a dining room applauding his star.