Peggy Ferguson of London, Worcestershire and New York wouldn't have dreamed of missing the New York City Ballet International Committee's "autumn meeting" at the Watergate last night.

"It's so exciting," she said, a striking presence of blond hair and black velvet.

"I just wish my husband were here. But the Hong Kong market is all upset. He's so perky. I miss him . . . You know, when you live in a foreign country it makes you so proud to be an American . . . We also have a place in New York. The more I live abroad, the more I need a place in New York."

The collection of sparkling diamonds and yards of pearls swirling through the Riverside Room for the 6 o'clock buffet last night would have done Cartier proud. A dazzling collection of blue-blood ballet supporters here for their meeting as well as for the ballet's opening night at the Kennedy Center, the guest list at the buffet dinner read like America's social register.

There were the Picots of New York and Paris, the Muellers of Delray Beach, the Lebermans of Dallas, the Mathewses of San Antonio, the Tylers of Lake Forest and more.

"You look just marvelous," said Marion Tyler to Patricia Patterson, chairman of the International Committee, the wealthy fund-raising arm of the ballet. "But you're too skinny."

"Too skinny? You can never be too skinny," said Patterson.

"Well," resigned Tyler, "I guess you can never be too skinny or too rich."

Started by Patterson in 1979, the committee raises money for the prestigious NYCB troupe's travel expenses. There are 100 members of the committee. They each pay a minimum of $1,000 to join.

"So we manage to raise at least $100,000 a year for the company to travel," explained Patterson. "And we get to travel. Every year we hold the meeting in a different city or country--Fort Worth, Paris, London. Next year we do Copenhagen. Everyone comes."

Like Donna Rautbord of Chicago, blond and bejeweled in brown taffeta.

"Now that's a low-cut dress," mumbled one man -- who would identify himself only as a "consultant" -- as she rustled by. It was.

"My friends call me Sugar," explained Rautbord. "I became involved with the New York City Ballet because Chicago didn't have its own company until very recently . . . I hope we have given them some moral support . . . It's been wonderful. Paris was very exciting, bright, gay."

Carol McKay of Fort Worth first became involved with the ballet last year.

"We gave a party for the company at our ranch when they were in Texas, and I've been interested ever since," said McKay. Her husband, William, is a rancher and car dealer.

The 200 dined on salmon and neatly arranged roast beef, which reflected off mirrored platters. Twinkling candles melted scarlet wax down tall silver candelabras. The desserts were the best. Chocolate pastries from the Watergate that no one finished.

Basic black prevailed. Silk, taffeta and velvet. It showed up marvelously against the gems.

There was at least one dissenter, however. Frances Kennedy, wife of Roger Kennedy, director of the National Museum of American History, wore yellow. A chiffon top and fur skirt. There was some green in the skirt.

"It's maribou," she said. "But I asked Smithsonian Secretary Dillon Ripley and he said it was okay. Maribou isn't an endangered species."

Soon 8 o'clock came. The lights blinked and it was curtain time.