Four hours before the concert. Four hours before Dudley Moore, who, as a result of $250 million in combined grosses from "Foul Play," "10" and "Arthur," can sit anywhere he wants in Hollywood, was about to put himself in the hardest seat he could find. He had come to debut, and it was a risk. His identity was at stake on the stage, at the huge Bosendorfer grand, and there would be nearly 700 self-appointed superiors in the audience at Manhattan's Metropolitan Museum of Art waiting for a laugh.

"This thing tonight," he said in a room backstage Sunday, "when I'm intimidated I get as paranoid as anybody, my fears seize up, but if I can remember this is something I enjoy, if I allow myself to remember that I . . . I don't really like challenges," he said. "This thing tonight, it's either that easy or a hundred times more difficult. I just want to psych myself up and remember that I enjoy this, that I love this music and I" -- he looked at the clock on the wall -- "and I better go."

He jumped up and picked up a shopping bag. "Christmas presents," he said. Inside there was a replica antique sculpture of a standing crane, a replica 17th-century three-inch sculpture titled "Dog Scratching Ear" and a profile of an Egyptian owl, all of which he bought at the museum store on his credit card. "They're for Susan," he said, "Susan Anton," the six-foot, strapping former Muriel cigar girl who has become a rock 'n' roll singer. She was waiting for Dudley Moore at their room in the Waldorf Towers, and he began walking out through the labyrinthine basement halls at the Metropolitan -- past wrapped paintings and life-size wooden horses -- until he reached the foggy 5 o'clock air of the Fifth Avenue dusk.

He began walking east to Park Avenue, raising his voice because of the cabs that were shooting by. He huddled the museum bag under the arm of his white sheepskin coat. "I was surprised by what happened with 'Foul Play,' " he said, "and by what happened with '10,' although a lot of that probably had to do with Bo Derek. I was amazed though, by what happened with 'Arthur.' I wasn't really lucky though, I can't call it lucky. It was the result of my training. I made the most of my opportunities." He did not look relaxed. He finally hailed a cab. He leaned his 5-foot-2-inch frame back and immediately pulled out bills with which to pay the driver, who slid open the glass wall and yelled back, "Do you mind if I ask you a question?" "Just one question." His name was Joe Paterno, and he hadn't yet missed a See MOORE, B3, Col. 1 MOORE, From B1 green light. "Do you really play the piano?"

"Yes," said Dudley Moore, "I really play."

"Because I noticed that you always play something in the movies, and I wanted to know if that was really you playing."

"Yes," said Dudley Moore, playing with the bills, "that's me."

"Because you're really good. I mean you're funny, but your playing is really good."

"Thank you," said Dudley Moore, fanning out the bills slightly.

"Now you can go back to what you were doing," said Joe Paterno, hitting another green light and then making a U-turn around an island. "That's all I wanted to know." He let Dudley Moore off in front of the Waldorf Astoria Hotel on Park Avenue. Moore stepped out of the cab and looked up at the building. "I need a steak and a bath," he said.

Moore, who is now 46, had represented -- with his "Beyond the Fringe" partners Jonathan Miller, Peter Cook and Alan Bennett -- part of the rebirth of the English theater that rose in the late '50s when the vitality of the new bunch of rebels created stage work that stepped away from the postwar years and rode hard the modern era. Moore and his "Beyond the Fringe" renaissance boys offered the bumptious topicality of a new order of Oxford-Cambridge vaudevillians: elite, Punchy and stropping almost anything in sight with their stage-sword banter. "It was a period when I was incredibly ambitious and wanted to do it all and thought that we could," says Moore.

"Beyond the Fringe" stirred its nation. It went from Edinburg to London, where it ran for two years, and from London to New York. Moore became an esoteric international star. He and Cook put together a comedy series on the BBC that was vastly popular and made a series of the kind of movies that defined English young comedy in the mid-'60s: "The Wrong Box," "Thirty is a Dangerous Age, Cynthia," "The Bedsitting Room" and "Bedazzled." He and Cook put together another show, another big hit, "Good Evening." In 1966 Moore married model Suzy Kendall. That marriage lasted for two years, and then in 1975, he married Tuesday Weld, from whom he was divorced in 1980 and with whom he has a 5-year-old son, Patrick. Now he shares a house by the water in Marina Del Rey with Anton, and the two of them eat health food together.

Through it all, he stayed with his music -- playing jazz on the BBC and classical music for himself, writing film scores occasionally and listening to Erroll Garner. He moved to California, and his drive thawed somewhat, his English brittleness took the sun. He discovered health food. He grew passionately involved with psychology, and after he was chosen for the 1978 movie "Foul Play," a picture for which he managed to contain his enthusiasm, he had one of the quintessential California experiences: Blake Edwards was in his therapy group; he made "10."

"Twenty years ago I was very obsessive, very repressive. I'm, now, I'm more able to see where I am. I just feel more at home with myself." He stretched his leg out on the couch and looked away. "I know who I am." He groped a little and reached. "I started with therapy in 1964 and went through five therapists. Three or four years ago I started in group therapy, I, sort of, began to coagulate. It was a hard, long process, and I now feel I know who I am, what the price is of doing certain things, and I came to the point which, I came to therapy to change -- and I --" Dudley Moore broke off and then looked up with a small, serious little smile. "I just found out I don't have to change." He stopped once more. "I always feel I ought to change," he said, "but I found out I don't really have to now."

By 9:30, Moore had cleared Bach and Mozart ("He was clear if not decisive on the K296," a man in a turtleneck said to a woman leaning on a cane during intermission). The New Yorkers, rubbing camel-haired shoulders, watched as his little body sat erect in evening clothes, with schoolboy posture, and his hands took the keyboard. His suit and his features and his hair had the inky definition of a Disney drawing, but this was not Mickey Mouse reaching up to shake Stokowski's hand in "Fantasia": Dudley Moore had prepared for this recital for 36 years.

When the lights dimmed again he sailed into a sweet and reeling Delius sonata with the distinguished violinist Robert Mann. It got a good hand, and Moore and Mann brought out Stanley Drucker on clarinet for the last piece, a happy, jouncing Bartok Contrasts with lots of musical Beep-beep! exclamations from the clarinet, Yah-yahs! from the violin, and Brrrun-runnns! from the piano.

Mann and Drucker smiled through it, but Dudley Moore worked in first gear. He plowed on, playing well if not exuberantly, and when the last piece was done, the Metropolitan crowd let him know he'd done okay, he was more than the novelty number flown in from the Coast to show that in fact, if a dog could dance the mazurka, if a movie star could run the country, then they supposed Dudley Moore could play Bartok on 83rd Street. They gave him a good hand and a couple of bravos and a few of them even stood, although none stood taller than Miss Susan Anton of Marina Del Rey, Calif. Her magnificent tan reddened under her forelocks when Dudley Moore took his bow, and her long arms (which seemed to stream out uncontrollably from her ersatz Afghan shepherd's vest) met at the hands in a frozen clap as she watched the rest of the house applauding her man. The applause he got was not the wild clubby tears he would have gotten from his friends on the Coast, but controlled affirmation for a proficient workman who hadn't missed a note on some very hard pieces his first time out.

After the first set of bows a small slew of photographers rushed up to the front of the stage in the exquisite, soft-lit Grace Rainey Rogers Auditorium, and the seasoned began to slough up the carpeted aisle and down the elevators toward their lamb's wool overcoats and Sunday night casual wraps. In a room offstage, Dudley Moore signed autographs. He smiled restrainedly; he had beaten the devil, if not soundly. He had won, in his life, the latest in a series of triumphs of moderation.

Nearby, Susan Anton grinned from a couch. A professional musician stood and watched him with slightly concealed irritation at the mob's attention. He was, after all, on the distinguished calendar of concerts that would include Andre' Watts, Emanuel Ax and Russian emigre' Alexander Peskanov.

"He's adorable," said the woman. "I suppose we musicians need this sort of thing," she said, heading off for an autograph. In the morning, Moore would fly back to California. He had just finished "Six Weeks" with Mary Tyler Moore, and he was on to "Valium" for Marshall Brickman and then "Unfaithfully Yours," a remake of the Preston Sturges picture, for Howard Zieff. But that was Hollywood news; this was Manhattan.

Downstairs, a middle-aged man in steel-rimmed stockbroker's glasses put on his dark, heavy overcoat. He stood with a friend who appeared to be a colleague. "He hit his notes," said the man in the heavy overcoat. "He wasn't really all that bad. Not at all."

"No," said his friend, "not bad."

"Did you see his movie?" said the man in the heavy overcoat.

"No," said his friend. "Which one?"

" 'Arthur,' " said the man. "He played a drunk."

"Oh," said his friend. "A drunk!"

"He did all right anyhow," said the man in the heavy overcoat, who walked out into the Metropolitan Museum's courtyard where there was a gray Manhattan drizzle. "A drunk," said the friend to himself, and followed to pull down a taxicab on Fifth Avenue.