"She looks like anybody else," sniffed a female guest at last Wednesday's R.B. Kitaj opening at the Hirshhorn Museum. "Oh, come on. She's gorgeous," countered her male companion. "She" was actress Diane Keaton, a close friend of the London-based American artist Kitaj, who was being honored with his first major retrospective. "She is also the first Academy Award-winner ever to attend a Hirshhorn opening," exulted Sidney Lawrence, public information officer for the museum.

According to sartorially well-informed observers, Keaton looked very up-to-date in velvet pedal pushers, pushed-down red-and-black striped knee socks and sling-back high-heeled pumps. "She's come a long way since the 'Annie Hall,' " they declared.

The auburn-haired actress came down from New York with an art critic friend, Frederick Tutten. Also among the 600-plus guests was Washington artists' model Marilyn Van Eaton McCarty, looking very odd and very fleshy in her homemade net dress that consisted chiefly of a G-string with a few strategically placed feathers; poet John Ashbery; and artist Raphael Soyer, 82, who admitted to being "a great admirer of Kitaj's work," but didn't comment on McCarty's costume.