"Roger Stevens certainly has a distinguished fan club," said a guest in the National Press Club library about noon yesterday. He was talking to Librarian of Congress Daniel Boorstin and looking around a room crowded with such notables as J. Carter Brown, David Lloyd Kreeger, Patrick Hayes, Lionel Hampton, Jean-Pierre Aumont and Claudette Colbert -- not exactly your average lunch-hour crowd at the Press Club.

"Some of them may be members of the Claudette Colbert fan club," said Boorstin, who was working his way through the knot of fans around the star to offer her a humble librarian's homage. "She still looks as lovely as ever," he mused, straightening a dark blue bow tie that looked like it might be made of velvet.

Colbert et al. were not the only celebrities at the reception and lunch for Roger Stevens, which the Press Club gave yesterday to celebrate the 10th anniversary of the Kennedy Center. Two of the glitteriest, Leonard Bernstein and Aaron Copland, missed the reception but arrived dramatically at the luncheon just after the ceremonies had gone on the air, while NPC president Joseph Slevin was introducing the head table. The arrival reflected not their superb sense of timing (though both of them have it at a virtuoso level) but the air-traffic problems that are benefiting rail travel between Washington and New York. Still presumably out of breath after his dash from National Airport, Bernstein, nonetheless, managed to give an impromptu tribute to Stevens that went well beyond the five-minute limit imposed by the Press Club.

But he had to wait in line for that. First, there were reminiscences by Kennedy Center board vice chairman Henry Strong and George Stevens of the American Film Institute, "one of those battered people who are Roger's tenants." Strong recalled the time 10 years ago when "we had an unfinished building, we owed money to everyone in the country, we had no credit and we didn't know what we were going to do. I asked Roger what he wanted to do when the building was finished, and he said, 'Get out of town.' "

George Stevens remembered early committee meetings in New York, when the committee was "debating on who would run the Kennedy Center and Roger just sat there smiling and knowing who would be running the Kennedy Center." He said he learned two things from Roger Stevens during those committee meetings: "that the way to deal with committees is to let them chase their tails . . . and that Roger Stevens has no interest in the democratic process."

As composer of "Mass," which was the first music performed in the Kennedy Center when it opened 10 years ago, Bernstein has a proprietary interest in the center and even says he likes its looks. "I don't think it's so ugly to look at," he said. "I take exception to that. I've grown accustomed to it." He recalled working on the music amid the noise of carpenters and masons who were rushing to finish the building: "My music, the hammers and the drills -- I still hear all those noises together. I feel a connection, and a prideful one, in the actual physical building."

He recalled "Jack Kennedy saying 'We've got to have this place -- what kind of a capital are we without a cultural center?' " He remembered that he was having trouble composing "Mass" when he visited Roger Stevens, in an intensive-care unit after a heart attack, shortly before the Kennedy Center was to open. "I asked him, 'Is there anything I can do for you?' and he said, 'The best thing you can do for me is to finish the "Mass," ' and I went home and I finished it, by God."

Perhaps the quietest person at the reception was the guest of honor. Roger Stevens talked about his plans for a conservatory ("It's already off the ground. Considerable money has been raised already"), his hopes for the future of musical theater in America, the runaway costs of new productions and the growing impact of the Kennedy Center on television with four telecasts coming up in the near future: "Mass," "Willie Stark," a special tribute to Lionel Hampton and the Kennedy Center Honors program. "We are trying to establish more rapport with the country at large -- give people a happier life and more contact with performing arts. There are still many, many cities that do not have live performing arts."

Then he fended questions from the audience on subjects that ranged from the food in Kennedy Center restaurants ("It bothers those of us who work there more than it does you. We have to eat a lot more of it . . . It's not great but pretty good . . .") to the condition of the Kennedy Center roof ("everybody gets a 20-year guarantee on the roof . . . everybody but the United States government"). Asked whether he really thinks Washington will be ahead of New York in cultural activities by the year 2000, he admitted that he says that mainly to disturb people at The New York Times -- and it works. But then he added that Washington may already be ahead in visual arts, and J. Carter Brown, sitting nearby at the head table, smiled broadly.

He discussed the state of criticism ("We have plays that do very well in spite of the critics") and warned small companies eager to come to the Kennedy Center that there are "risks" there as well as glory. Sometimes he took several minutes to answer a question, but most of the time he was short and to the point. "What do you expect to come out of the agreement between CBS and the Eisenhower Theater?" somebody asked. "Some money," Roger Stevens answered.

It was a virtuoso performance, though so quiet one might have missed noticing. And it helped to explain the size and quality of the Roger Stevens fan club.