Steamy or not, the welcome could hardly have been much warmer. There was President Reagan last night, greeting Pakistan's prime minister, who was here on an official visit one senior administration official described earlier as "an important symbol . . . so soon after the lifting of martial law and restoration of full constitutional government."

Mohammad Khan Junejo, 53 and "wealthy" as a State Department biography succinctly described him, arrived at the North Portico of the White House to all the pomp and splendor that traditionally await a visiting world leader. Towering over Reagan as they stood together with First Lady Nancy Reagan for yet another tradition, a session with photographers, Junejo was sober and unsmiling.

Later, in his toast, Reagan said the day's discussions with Junejo had been "upbeat, cordial and productive and will undoubtedly strengthen the bonds of friendship between our two nations." Pakistan, he said, "is moving toward the realization of its cherished democratic ideals."

Continuing, the president asserted that "even in the face of increasing Soviet pressures we stand by you in defense of your sovereignty. Pakistan's determination to see Soviet troops out of Afghanistan strengthens the resolve of free men everywhere."

Reagan did not specifically refer to either the administration's $4.02 billion aid proposal for Pakistan, or the controversy over nuclear proliferation, although Junejo touched on it scantily in his response.

"Mr. President, we appreciate the assistance the United States has extended to Pakistan since 1981," he began. "It has given a boost to our economic progress and it has bolstered our nation's self-confidence."

And later he stated simply, "We have offered various ideas for the renunciation of nuclear weapons."

The Pakistani leader's visit inevitably prompted some discussion of nuclear proliferation. Earlier in the evening, Rep. Rod Chandler (R-Wash.) gave a familiar response to a question on the subject: "The nuclear issue -- that's surely a message that will get delivered once again."

Another serious topic, drug abuse, came up when Nancy Reagan's press secretary, Elaine Crispen, responding to a query, confirmed that the first lady will meet today with the Rev. Jesse Jackson to discuss the subject.

But for the most part it wasn't a night for weighing in on the issues. The assembled guests, several of whom had Hollywood connections, had other things on their minds. For example, the royal wedding.

Actress Jane Seymour said she will be part of the ABC team on hand next Wednesday when Prince Andrew marries Sarah Ferguson. She has already had an interview with Prince Philip, and she told of asking him about his daughter-in-law to be. "He was referring to breeding in the family and spoke of something being co-bred and I thought he meant the children. And he meant the horses. So I did get a laugh out of him."

Seymour drew admiring glances from Nancy Reagan and Defense Secretary Caspar Weinberger in the lavender taffeta gown by the same designers who did Princess Diana's wedding dress.

For two husbands, it turned out to be a night to step on your wife's dress. President Reagan stepped on Nancy Reagan's figure-hugging apple green dress and laughed it off, saying, "The last time I did that was to the president of France's wife." David Flynn stepped on Jane Seymour Flynn's dress and she laughed it off saying, "He's got the world's biggest feet -- Size 13."

Bruce Boxleitner, star of "Scarecrow and Mrs. King," and his wife Kitty didn't try to conceal their excitement at being at the party. "This is the big show," said Boxleitner, looking at the Reagans inching their way through the crowd, which included big business, academia, government and the usual complement of multipurpose celebrities.

Boxleitner said he'd just filled in the former president of the Screen Actors Guild on Hollywood's current labor troubles, one of major ones being over the distribution of video tapes. "He was very interested. You know, when he was in the Screen Actors Guild he was instrumental in getting residuals for members."

Of reports that she wants to be cochairman of the Republican National Committee, Maureen Reagan said "nobody ought to be discussing" anything like that until after the November election. "We've got 1,300 Republican women running for office this time around the country and right now I'm too busy trying to get them elected."

"Cap" Weinberger told reporters that "the president will reply soon" to Soviet leader Mikhail Gorbachev on the subject of a summit. When one of writers chided that "I hear you've been gumming up the works," Weinberger drew himself up to a battle position.

"Surely, you could phrase it more tactfully," he replied.

After violinist Eugene Fodor performed for everyone in the East Room, President and Mrs. Reagan performed for them on the dance floor. The tune, "Second-Hand Rose," was one that proved a hit for Mrs. Reagan at the 1982 Gridiron Dinner. That night she poked fun at herself by singing a parody based on her image problems, and some saw it as a turning point in reshaping public attitudes about her.

Also at last night's dinner was "A-Team" star George Peppard, who said he had no idea whether President Reagan watched his show. "I'd have to ask," he said laughing, and then added quickly, "I won't ask."

If he had, he might have been pleasantly surprised. Earlier in the day at a luncheon for Junejo, the president's daughter Maureen told another guest that Peppard had written a letter to someone saying how pleased he was to be invited to the dinner.

"And I said, 'Daddy, be sure and tell him "The A-Team" is our favorite television show.' He said, 'I certainly will,' " she said.

She said that the show is her favorite and that her father had also come to like it: "Sometimes we play a little hooky in the evening and go in and watch 'The A-Team.' You know, he doesn't get to watch television because he works every night."

At the luncheon, Secretary of State George Shultz, celebrating his fourth anniversary on the job, commended Pakistan's "principled stand" against Soviet actions in Afghanistan. Looking across the room where Pakistan's Foreign Minister Jakub Khan, a former ambassador to Washington, was sitting, Shultz described how at the Chernenko funeral in Moscow, he, Khan and Pakistan's President Mohammed Zia ul-Haq had "stood apart."

"You remember, Jakub, how all those generals looked at us and we stood there and let them see us?" Shultz asked.

In his response, Junejo addressed U.S. concerns about nuclear proliferation in the region.

"It is equally our aim and desire to have our densely populated region free from the specter of nuclear weapons," he said. "If such a thing exists, it does not emanate from Pakistan."

Prime Minister Mohammad Khan Junejo, his daughters: Miss F. Junejo and Miss S. Junejo and son Mohammed Asad Ali Khan Junejo

Sahabzada Yaqub-Khan, minister of foreign affairs, and Tuba Yaqub-Khan

Mian Mohammad Yasin Khan Wattoo, minister for finance and economic affairs

Mian Mohammad Nawaz Sharif, chief minister of Punjab

Arbab Mohammad Jahangir Khan, chief minister of Northwest Frontier Province

Ejaz Azim, ambassador of the Islamic Republic of Pakistan, and Shahida Azim

Jamal Ahmad Khan, chief of Air Staff, PAF

A.G.N. Kazi, deputy chairman, planning commission

Abdul Sattar, secretary, foreign affairs

Michael H. Armacost, undersecretary of state for political affairs, and Bonny Armacost

John F. Akers, president and CEO, IBM Corp., and Susan Akers

James A. Baker III, secretary of the treasury, and Susan Baker

Hector Barreto, president, U.S. Hispanic Chamber of Commerce, and Ana Favrow-Barreto

Bruce Boxleitner, actor, and Kitty Boxleitner

James L. Buckley, judge, U.S. Court of Appeals for the District of Columbia, and Ann Buckley

James E. Burke, chairman, Johnson & Johnson and Diane Burke

Vice President George Bush and Barbara Bush

Sen. John H. Chafee (R-R.I.)

Rep. Rod Chandler (R-Wash.)

Rep. Richard B. Cheney (R-Wyo.) and Lynne V. Cheney, chairman, National Endowment for the Humanities

Sen. Thad Cochran (R-Miss.) and Rose Cochran

Barber B. Conable Jr., president, World Bank, and Charlotte Conable

Robert Denning, Denning & Fourcade Inc.

John W. Dixon, chairman and CEO, E-Systems Inc., and Doris Dixon

Lloyd H. Elliott, president, George Washington University, and Evelyn Elliott

Jane Seymour, actress, and David Flynn

Eugene Fodor, violinist, and Susan Fodor

Horton Foote, screenwriter, and Lillian Foote

Vincent Fourcade, Denning & Fourcade Inc.

Julian Gingold and Irene Gingold

Lawrence Goodman and Muriel Goodman

Sen. Howell Heflin (D-Ala.) and Elizabeth Ann Heflin

Deane R. Hinton, American ambassador to Pakistan

William H. Hudnut, mayor of Indianapolis, and Susie Hudnut

Harold Johnson and Elma Johnson

Karl Karcher and Margaret Karcher

George Keller, chairman, Chevron Corp., and Adelaide Keller

Darci Kistler, ballerina

Alan Ladd Jr., chairman of the board and CEO, Metro-Goldwyn-Mayer, and Tracy Ladd

James Lehrer, The MacNeil/Lehrer News Hour, and Kate Lehrer

Glenn Lowry, economist, and Linda Datcher-Lowry

William H. Luers, president, Metropolitan Museum of Art and former ambassador, and Wendy Luers

Cecil B. Lyon and Elizabeth Lyon

John O. Marsh Jr., secretary of the army, and Glenn Ann Marsh

Mary T. Meagher, Olympic gold medalist

Pat Murphy, publisher, Arizona Republic and Phoenix Gazette, and Betty Murphy

Richard W. Murphy, assistant secretary of state for Near Eastern and South Asian affairs, and Anne Murphy

David Paton, founder and director, Project Orbis, and Diane Brokaw, executive director, The President's Committee on the Arts and the Humanities

George Peppard, actor, and Joyce Peppard

Samuel Riley Pierce Jr., secretary of housing and urban development, and Barbara Pierce

Adm. John M. Poindexter, assistant to the president for national security affairs, and Rev. Linda A. Poindexter

Maureen E. Reagan and Dennis Revell

Donald T. Regan, chief of staff to the president, and Ann Regan

Frank Richardson, executive vice president, Wesray Capital Corp., and Nancy Richardson, editor of House and Garden magazine

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

Gloria Sachs, fashion designer

Norman Sandler, White House correspondent UPI, and Raeanne Sandler

Rep. F. James Sensenbrenner (R.-Wis.), and Cheryl Sensenbrenner

Joseph Shapiro, White House correspondent, U.S. News & World Report, and Janet Lottero

George Shultz, secretary of state, and Obie Shultz

Rep. Ike Skelton, (D-Mo.), and Susie Skelton

Kenneth W. Starr, judge, U.S. Court of Appeals for the District of Columbia, and Alice Starr

Caspar W. Weinberger, secretary of defense

Gen. John A. Wickham Jr., chief of staff, U.S. Army, and Ann Wickham.