Sylvester Stallone came armed with an answer for President Reagan in his latest hostage crisis.

"Let's put it this way," Stallone said last night as he arrived at the White House dinner for Singapore's Prime Minister Lee Kuan Yew. "I'm an action actor so I'd like to have a little action."

You'd hardly have expected anything less. This summer, right after the release of the TWA hostages, Reagan told of screening Stallone's then-new movie. "After seeing 'Rambo' last night," the president said, "I'll know what to do next time."

"Next time" turned out to be last night as the hijacked Italian cruise ship carrying an undetermined number of Americans entered its second day under Palestinian terrorists' control.

The crisis seemed to be on hold at the White House most of the evening. President Reagan was smiling his thumbs-up smile, Secretary of State George Shultz was smiling his all-purpose smile and Adm. William J. Crowe Jr., chairman of the Joint Chiefs of Staff, was smiling his all-in-a-day's-crisis smile.

"I'd rather not talk about it," Crowe told reporters.

For a few minutes after dinner, the president did discuss the day's dramatic events with reporters. "We're dealing with all the other countries involved, Italy first of all. So I think we haven't got any comment we can make." When someone asked if the Sixth Fleet knew where the Italian cruise ship was, Reagan said, "Actually no, they were in another part of the Mediterranean." Asked about a report that the captain urged that no action be taken, Reagan said, "We don't know if that was really the captain."

As seems to be the custom these days at the Reagan White House, celebrity guests took much of the focus off any serious problems confronting the administration. For Stallone, having the president tell the world he'd seen his film was good for the ego. "It's always flattering to have the highest person in the land admire your work," the actor said as he and his date, actress Brigitte Nielsen, arrived. He and the president always had "a good relationship," he said, and in fact, he said he was reminded that he owed the president a poster "and I want one of him."

Stallone may have been alone in openly giving advice to the president but not in lending star quality to the guest list. Right behind him came a breathtaking Raquel Welch, who said she'd been to the White House during the Ford administration.

"I don't know if I asked for it," she said of last night's invitation, "or if I'm on the list of people to decorate state dinners."

In any case, she "decorated" it spectacularly. She wrapped herself in folds of white jersey, and when she entered the East Room Vice President Bush was there waiting.

Michael J. Fox, the diminutive star of the TV series "Family Ties," claimed he wasn't nervous, though he'd never met a president before.

Wearing a black steward's jacket, he said he didn't know if the Reagans watch his show but "I know he saw my movie 'Back to the Future' when he was recovering." When a reporter suggested Reagan might ask him for his autograph, Fox and his date, Nancy McKeon, an actress appearing in the series "The Facts of Life," both beamed. "I'll give it to him if he does," Fox said.

Also making a splashy entrance was Natalie Cole, a standout in a red strapless gown with vertical ruffles. Nielsen (whom a White House social aide identified as Stallone's fiance'), wore a figure-hugging black crepe dress with a lace and velvet evening coat. She finished off the outfit with black lace gloves. Definitely not in the background, First Lady Nancy Reagan wore a grape-and-gold silk dress that she had first worn for Queen Elizabeth's visit in 1983.

The Reagans welcomed the Lees on the North Portico on the soft autumn night with yellow chrysanthemums starting to bloom along the circular drive. After the dinner of filet of veal with ginger sauce, mandarin sunflower salad and lime souffle' with fresh figs, the prime minister praised Nancy Reagan for seeing to so many details of the dinner in his honor. He mentioned her campaign against drug abuse and her visit to "the rubble of Mexico City." Then he said, "I noticed her approval rating at 71 percent," paused dramatically and added, "ahead of the president." The dining room erupted into laughter. "Mr. President, your staff has to shape up," said Lee.

In his toast, President Reagan had praised the prime minister as a man of "principled vision" and said that America and Singapore were joined in history and philosophy. "Our two peoples at first glance may seem worlds apart . . . nations of hard-working immigrants."

The stars gravitated to the Reagans. Welch twice interrupted the president as he was talking with reporters to tell him she hoped they could have a dance together, and he smiled reassuringly at her. She was later seen keeping up with a rapidly twirling George Shultz. Nancy Reagan and Cole, who has talked openly about her recovery from drug addiction, discussed the first lady's antidrug campaign, and the singer volunteered her services. Fox cornered Nancy Reagan to say he hadn't meant to be disrespectful to the president in "Back to the Future" -- part of the film is set in the 1950s and Reagan's name appears, to humorous effect, on a movie marquee -- and she assured him that she and the president had enjoyed the movie.

Last night's guests were entertained by Karen Akers, who filled in at the last minute for singer Peggy Lee, who had double-bypass surgery earlier this week. Akers, who is currently filming "Heartburn," said she had to juggle her schedule yesterday between rehearsing and going to the dentist. "Jim," she said of her husband, "ended up doing the car pool."

Her schedule juggling and her hearty theatrical style generated effusive praise and applause from the president and his guests. When he mentioned "Nine," the play that first brought Akers attention, he said, "Incidentally in that musical 'Nine,' you were a 10." Referring to her last-minute substitution, Reagan added, "I think in the future -- several times -- I will pick out someone in ill health and invite them."

Sharon McAuliffe, the teacher who is training for the Shuttle Challenger mission, sat next to the president last night. She said he had talked about his Hollywood career. "He told us a lot of stories about when he was in films," she said. "He also said maybe I could take some papers to grade with me in space. One of the nice things about this year was I didn't have any papers to grade. I didn't miss it." The list of guests at last night's White House dinner for the prime minister of the Republic of Singapore:

Lee Kuan Yew, prime minister of the Republic of Singapore, and Mrs. Lee

Prof. S. Jayakumar, minister of home affairs and second minister of law

Yeo Cheow Tong, minister of state for health and foreign affairs

Tommy T.B. Koh, U.S. ambassador of the Republic of Singapore, and Mrs. Koh

Kishore Mahbubani, permanent representative of Singapore to the United Nations, and Mrs. Mahbubani

Peter Chan, second permanent secretary, Ministry of Foreign Affairs

Barry Desker, director of the policy, planning and analysis division of the Ministry of Foreign Affairs

Lee Young Kiat, physician to the prime minister

Tan Guong Ching, principal private secretary to the prime minister

Chan Chin Bock, alternate chairman, Economic Development Board of Singapore, and Mrs. Chan

Karen Akers, performing, and James Akers

Shirley Temple Black, former U.S. chief of protocol, and Charles Alden Black, president, Mardela Corp.

Susan Brody, art dealer, New York City

Mario Buatta, interior designer

Warren E. Buffett and daughter Susan Buffett of Omaha

Vice President Bush and Barbara Bush

Lou Cannon, White House correspondent, The Washington Post, and Mary Cannon

Natalie Cole, singer, and Karl Nurse

Alec P. Courtelis and Louise Courtelis, Miami

Adm. William J. Crowe Jr., chairman, Joint Chiefs of Staff, and Shirley Crowe

Arnaud de Borchgrave, editor in chief, The Washington Times, and Alexandra de Borchgrave

Sen. Jeremiah Denton (R-Ala.) and Jane Denton

Dr. James Dobson, author, and Shirley Dobson

Fernanda Eberstadt, author

Theodore L. Eliot Jr., president, Asia Foundation, and Patricia Eliot

Joe Ewalt, White House correspondent, RKO Radio, and JoAnn Ewalt

Malcolm Farmer III, city council member, Providence, R.I., and Susan Farmer, Rhode Island secretary of state

Michael J. Fox, actor, and actress Nancy McKeon

Max. L. Friedersdorf, assistant to the president

Joseph Gildenhorn and Alma Gildenhorn, Washington, D.C.

Vartan Gregorian, president, New York Public Library

Alan E. Heimert, professor, Harvard University, and Arline Heimert

William Hyland, editor, Foreign Affairs, and Evelyn Hyland

Donna Karan, fashion designer, and Stephan Weiss

Donald R. Keough, president, Coca-Cola Co., and daughter Shayla Keough

Sharon Christa McAuliffe and Steven McAuliffe

Robert C. McFarlane, assistant to the president for national security affairs, and Jonda McFarlane

Robert L. McNeil Jr. and Nancy McNeil, Wyndmoor, Pa.

Frank L. Morsani, chairman, U.S. Chamber of Commerce, and Carol Morsani

Harry Newman and Anne Newman, Long Beach, Calif.

Rep. George M. O'Brien (R-Ill.) and Mary Lou O'Brien

Richard E. Oldenburg, director, Museum of Modern Art, and Lisa Oldenburg

Robert B. Oxnam, president, The Asia Society Inc., and Barbara Oxnam

Rep. J.J. Pickle (D-Tex.) and Beryl Pickle

George S. Pillsbury, president, Sargent Management Co., and Sally Pillsbury

John Portman, architect, and Jan Portman

Chesley Pruet and Elizabeth Pruet, El Dorado, Ark.

Sen. David Pryor (D-Ark.)

Donald T. Regan, chief of staff, and Ann Regan

John M. Richman, chairman, Dart & Kraft Inc., and Priscilla Richman

Edward J. Rollins, former assistant to the president, and Sherrie Sandy

Selwa Roosevelt, chief of protocol, and Archibald B. Roosevelt Jr.

J. Stapleton Roy, U.S. ambassador to Singapore, and Elissandra Roy

Martin Segal, chairman, Lincoln Center for the Performing Arts, and Edith Segal

Barry Serafin, ABC News, and Lynn Serafin

George Shultz, secretary of state, and Helena Shultz

Rep. Bud Shuster (R-Pa.) and Patricia Shuster

Sylvester Stallone, actor, and actress Brigitte Nielsen

Sen. Steve D. Symms (R-Idaho) and Frances Symms

Margaret Leng Tan, concert pianist

Andre' Tchelistcheff and Dorothy Tchelistcheff, Napa, Calif.

Robert Tilman, dean, School of Humanities and Social Sciences, North Carolina State University, and Jo Tilman

Suki Ullrich and Jie K. Song, Annandale, Va.

Joseph V. Vittoria, president, Avis Inc., and Luciana Vittoria

Raquel Welch, actress, and Andre' Weinfeld

George M. White, architect of the Capitol, and Susanne White

Paul D. Wolfowitz, assistant secretary of state, and Clare Wolfowitz

F. Clifton White and Gladys White, Greenwich, Conn.