First he got a hug from his wife. Then his mother. And then his father, the president of the United States.

Ron Reagan Jr. had just made his first appearance on the stage of the Metropolitan Opera House in New York.

"We all tend to be a little cynical about the human race, even about ourselves," said the president. "Then you see something this way and say, 'Any creature that can do anything that beautiful, he must be remarkable.'"

Ron Jr. beamed, an "aw shucks" grin spreading from one ear to the other.

The Reagans ended a weekend trip to New York last night by watching their son dance at a gala benefit performance of the Joffrey Ballet. More than 3,000 people were packed into the Met for the company's major fundraiser of the year. The main Joffrey company, the second-string Joffrey II and Diana Ross all performed. Not many were denying that the president's appearance helped things along. But it also made for some anxious dancers.

"Were you nervous?" somebody called out to Ron Jr. as he waited afterward for his father at a reception room at the Met.

"Nervous," affirmed Ron, "very nervous. Never danced on anything that big before." He meant the stage of the Met. He's in the Joffrey II Ballet, considered the farm team for the main company. Usually they dance in small towns and colleges.

Although it was widely reported that this was the first time the Reagans were seeing their son dance professionally, one friend of the Reagans insisted this was not so. Betsy Bloomingdale, the wife of the founder of Diners Club, said during the weekend that the Reagans had actually seen Ron Jr. perform with another company about a year ago in California. Still, it had been a long time since then.

"We waited until he said he was ready for us," said the president to reporters and cameramen who recorded every hug and warm word between the son and father, who are sometimes said to have a distant relationship. Ron Jr. smiled again. For the meetig with his father, who hadn't seen him recently until he leapt across the stage, Ron Jr. had changed from his burnt-orange tights into a blue bathrobe, red sweat pants, and down-filled moon boots which presumably kept his dancer's feet warm.

He performed in the third ballet of the evening, entitled, "Unfolding." A Joffrey spokesman called it "an abstract neoclassical ballet" about "relationships" between the four dancing couples. Ron Jr., like the others, had several dancing solos with his partner Melissa Zanzola. He picked her up, swung her across his body, onto a hip, or in the air.

There were two curtain calls after the performance. Ron Jr. got an enthusiastic hand, but it was another dancer named Edward Morgan and his partner, Julie Janus, who drew the biggest applause.

Before their son's performance, the Reagans had behaved like any anxious parents. At dinner on Saturday at Le Cirque, an elegant East Side restaurant full of purple tulips and such diners as Bianca Jagger, the president had talked to Betsy Bloomingdale about his son's debut.

"Here's your son, dancing in front of all these people for the first time," said Bloomingdale, who smoked a Cigarillo after dinner, "and you're the president of the United States. Well, wouldn't you be nervous?"

The Reagans had been dinner guests of Bloomindale and her husband, Alfred, at the restaurant long favored by the first lady. Others in the presidential party at the corner table, a frequent haunt of New York Gov. Hugh Carey and actor Dustin Hoffman, included Claudette Colbert, the actress, and Jerry Zipkin, the man about town.

Not at the table was Jagger, who was sitting nearby with a gaggle of other guests who looked thin and rich.

Table-hopping was a popular activity, and so after dinner, the Warhol table hopped over to Reagan. More than a few other diners, their eyes riveted in shameless fascination, watched a conservative Republican president warmly greet a liberal chapter of the '60s.

Last night at the Met, Nancy Reagan served as honorary chairman of the benefit, which netted almost $200,000 for the company last year. The Reagans sat in the presidential box with the Bloomingdales, Ron Jr.'s wife Doria Reagan, Carey, Saudi Arabian Ambassador Faisal Alhegelan and his wife, Nouha, and John Coleman, owner of the Fairfax Hotel.

Here's what Ron Jr. said about his performance: "Pretty good."

Here's what Robert Joffrey, artistic director of the company, said about it: "I think it was a wonderful debut for him at the Met."

Ironically, Joffrey's company stands to lose as much as $250,000 because of Reagan's proposed cuts in the National Endowment for the Arts budget. Joffrey didn't mention this last night. Neither did the president.

When Reagan greeted his son, he also shook hands with the rest of the cast. They had been fidgeting and fussing, flexing their toes in apparent trepidation at meeting somebody who was not just another father of a dancer.

"Well," said the president to them, "you all look very beautiful, really."

"When the ballet finished," said Joffrey II artistic director Sally Bliss during a party after the gala, "the president looked at me and said, 'Can I breathe now?'" Reagan sat next to Bliss during the performance. She was the one who plucked Ron Jr. out of the Joffrey school in November 1979, and while she admits that selecting a president's son has brought wonderful publicity to the company, she also insists that she thought at the time he was just another dancer.

"I saw him and I said, 'I like that boy. Who's he?' and the teacher said: 'That is Ron Reagan.'"

"It's a fluke," Bliss continued. "I didn't know. During the ballet I turned to his father and said, 'I can't believe this is happening.'"

Bliss said that Ron Jr.'s performance was a difficult one, especially one particular pas de deux. "He had to lift this girl over his back," Bliss said, "and he really was under pressure. But he didn't goof."