"Cicely is beautiful!" said one wide-eyed guest.

"Miles is cool," said another, after shaking hands with the jazz great, "what more can you say?"

She wore all white and he wore all black, except for his red-rimmed glasses. Miles Davis and Cicely Tyson, husband and wife, were the undisputed stars of the party following Tyson's opening in "The Corn is Green."

Producer Zev Bufman, head of the Elizabeth Theatre Group that presented the play, was the host of Thursday evening's black-tie, post-performance supper. It was held at Dominique's restaurant, which was festooned with red, white and blue balloons and carnations for Bastille Day.

The Elizabeth Theatre Group, which lists Bufman and Elizabeth Taylor as coproducers, has had a disappointing opener with "Private Lives" in New York. The show has suffered because of Taylor's frequent illnesses and resultant missed performances. The theater group series offered three plays to subscribers, of which "The Corn Is Green" is the second, but until recently the third play was undetermined.

"We're waiting for George C. Scott to finish a movie, and then he and Jason Robards will open in 'Inherit the Wind,' " said Bufman. Though he did say the play would open in New York, he did not know precisely when. He said the Robards-Scott combination should be "explosive." Referring to "The Corn is Green," he commented, "This is exciting, like newborn babes."

The evening started late. Most of the cast arrived near midnight, and Davis and Tyson made their entrance still later. But no one seemed to mind. They were too absorbed in gazpacho and grilled salmon.

For dessert, they devoured chocolate truffles, except for Miles Davis, who requested "white ice cream."

Did he mean vanilla? asked the waitress.

No, he replied, white. A heaping bowl of vanilla ice cream was what arrived.

House Speaker Tip O'Neill was there with his daughter, Rosemary, talking with Mayor Marion Barry. Vernon Jordan, ex-president of the National Urban League, and Julian Bond, Georgia senate member and civil rights leader, chatted amiably, and Tyson introduced Al Lewis, recently appointed ambassador to Sierra Leone, as "one of my dearest friends."

The guests, who also included Father Gilbert Hartke of Catholic University, George Stevens of the American Film Institute, and a smattering of congressmen, clapped when actress Mia Dillon arrived, bearing a bouquet of roses. When Tyson made her entrance, resplendent in a white beaded gown, some guests gasped and the room burst into applause once again. Mayor Barry read a proclamation naming July 14 Cicely Tyson Day in Washington. Because the restaurant was rather dimly lit, he read it by candlelight.

Few of the men complied with the "black tie" on the invitation, but the women wore lots of chiffon and pearls. Chen Sam, who is Elizabeth Taylor's spokeswoman, was particularly dramatic with her sweeping caftan and long, dark hair.

"Do I look alright, Joey?" Tyson asked makeup artist Joey Mills as she posed for yet another photograph. The guests looked at each other incredulously.