As far as Helen Hayes is concerned, she hasn't been a great actress. "I've been a popular actress," she said this week. "I had what they used to call star quality; I could somehow connect with an audience. But I've had no illusions about the difference between art and popularity."

Hayes made her last stage appearance in 1971, in a production of "Long Day's Journey Into Night," at the Hartke Theater here. She was, she said, "ordered" to quit by her doctor, who said her recurrent attacks of pneumatic bronchitis were the result of her being "allergic" to the theater. In the years since she has made several movies that she used as "a sort of decompression chamber" from a career that began at the age of 5. She has little interest in these movies and will do another, she said, only "if I need the money for something special," like a painting she just paid for with a soon-to-be-shown television movie.

Now 81, she keeps a busy schedule from her home in Nyack, N.Y., lobbying for home care for the elderly and the Helen Hayes Hospital, a rehabilitation facility on whose board she's served for 37 years. "My next movie will be something about the metamorphosis of an actress into a hospital," she joked.

She has gone through all the major phases of an actress: child star, inge'nue, leading lady and the character parts reserved for older women. Her more than 70 roles onstage include the leads in "Pollyanna" (1917), "Caesar and Cleopatra" (1925), "Mary of Scotland" (1934), "Victoria Regina" (1937-38 and 1939), as well as Viola in "Twelfth Night" (1941), Amanda Wingfield in "The Glass Menagerie" (1948 and 1957 and on television and a 1962 tour), Mrs. Antrobus in "The Skin of Our Teeth," Mrs. Grant in "The Front Page" -- a character patterned on her mother and co-written by her husband, Charles MacArthur, Veta Louise Simmons in "Harvey" (1970) and Mary Tyrone in "Long Day's Journey Into Night" (1971).

For all her disinterest in films, she has won two Academy Awards, the first in 1931 for "The Sin of Madelon Claudet" and the second in 1970 for "Airport."

Recently the National Theater, where she made her first appearance in 1905, unveiled a portrait of her. After the ceremonies she said that actors rarely give a performance they themselves recognize as great, and in her career she had experienced "that miracle" only once, in a performance of "Mary of Scotland," in Columbus, Ohio.

"I think she got tired of me messing around with her life and she came down and took over one night," Hayes recalled. "At the end there was no applause. The entire audience went into the alley outside the stage door, and when I came out they just sort of parted like the Red Sea, and applauded." Actors are mystified by these happenings, she said, because they don't know how they can repeat the performance.

Hayes, who will be escorted at this evening's ceremonies by her son, James MacArthur, has received numerous awards and honorary degrees. But the one that "startled me most," she said, was a Grammy she won for a record of her reading the Bill of Rights. "Duller reading you never heard," she said. "But I was thrilled. I felt like a country and western singer."

Characteristically, she says the Kennedy Center honor is undeserved. "I feel sheepish . . . But I am thrilled too. I hope we'll all get through the evening without anyone saying, 'I protest!' "