He gave a luncheon for her Sunday afternoon, and in the evening, at the wheel of his gleaming Rolls-Royce, he drove her to a party at a Washington in-spot. Monday they dined on caviar at the Iranian embassy. Tuesday he escorted her to the world premiere of her new film, The Blue Bird. Wednesday he took her to the harness races in Maryland, where they held hands and she sat in his lap. Thursday night they partied again.

He is Iran's dashing, gregarious ambassador to the U.S., Ardeshir Zahedi; she is Elizabeth Taylor, and together they are the talk of two capitals. "I just laugh at stories we are in love," shrugs Zahedi. "I have known Elizabeth and her husband for 14 years. She is a friend. I'm not going to marry Charlie Chaplin or James Mason, and they are both my friends too."

It is not Zahedi's friendship with Chaplin, however, that may threaten his dazzling diplomatic career. Reportedly embarrassed by his envoy's flamboyance, the Shah was rumored to be considering calling him home to Tehran. ("He went too far, publicly smooching with Elizabeth," says a fellow diplomat. "It is not the image the Shah wants.") If true, Zahedi's fling with Taylor could deprive Washington of its host with the most. A profligate party-giver and -goer, the ebullient 48-year-old ambassador has become the Sun King of the capital social whirl.

Even as official Washington was speculating, Zahedi hosted a cocktail party at New York's Kennedy Airport to celebrate the beginning of nonstop jet service between the U.S. and Iran. Topping the guest list: the ubiquitous Liz and her hairdresser, who joined 149 other passengers on the round-trip junket.

Though Zahedi, who stayed behind, urged the travelers to enjoy themselves, and to "pinch the person seated next to you," Taylor escaped unmolested. Escorted by Zahedi's cousin Firouz, she arrived in Iran to the howl of welcoming sirens and was rushed by motorcade to the Tehran Hilton, where she demanded, and got, the royal suite. Minutes after Liz checked in, word swept through the hotel that she had lost her fabled jewelry box. Rushing to the scene, relieved plainclothesmen discovered that the missing article was only a package of Glenfiddich Scotch.

In Iran Liz lunched with Ambassador Richard Helms, dined at Zahedi's palace (he phoned a long-distance welcome), consulted a doctor about some stomach trouble and toured a mosque, where she was encouraged to stamp and clap to create an echo. (If the visitor hears seven echoes, she is said to be "pure of heart." Liz heard them.) Some Iranians found her a letdown. The celebrated movie star, snarled the women's magazine Zan-E-Ruz, was merely "a fattish, short, big-busted woman with poor makeup, and totally out of fashion." It recommended she go on a diet. Undaunted, Liz washed down her caviar with vodka. Later local tastemakers clucked when Taylor showed up for a tea party meeting with Empress Farah Diba wearing a funereal unstylish black dress. And when the head of the Iranian Committee of U.S. Bicentennial Celebrations threw a cocktail party, Liz was an undiplomatic no-show.

Back in Washington, Ambassador Zahedi, who jogs in place in his bedroom for 25 minutes every morning to keep his weight under 180 pounds, remained a study in perpetual partying. (He usually nurses one Scotch at receptions, rarely mixes wine and whiskey.) Flying to Houston for back-to-back receptions, he returned to the capital to host a dinner party for David Frost, at which Zahedi himself grilled the lamb kabobs. Monday he gave a dinner for U.S. Representative to the U.N. William Scranton, and on Tuesday he went to a reception for Vice-President Nelson Rockefeller. Wednesday he gave a dinner dance for retiring Sen. Stuart Symington, and Thursday he flew to New York for diplomatic business.

The popular Zahedi is almost aggressively unapologetic about his socializing. "What is the job of the ambassador?" he asks. "To just meet all his colleagues and eat with them, or to try to know the people in a country?" At his parties, Zahedi avoids monotony by constantly changing his menu ("If people like caviar, I give it to them. If they like peasant soup, I give them that") and by blueprinting each evening. "If you have people who don't like to dance, and you have music, it makes them crazy, gives them a headache," he explains. "One night everyone wanted to talk, so we had two violins. It's nice background music." Above all, Zahedi strives for a convivial atmosphere. "Nobody comes to your home because you are going to give them food," he observes. "They have enough food in their own homes."

The son of a leading Iranian family, Zahedi was once tortured by Premier Mohammad Mossadegh's police. His father was named premier by the Shah after engineering the 1953 revolution that ousted Mossadegh. Educated at Utah State, Zahedi worked in the Gary, Ind., steel mills, California fruit groves and on the Alaska railroad. He was married to the Shah's daughter, Princess Shahnaz, in 1957, but the marriage ended in divorce in 1964. "I don't think I'll ever marry again," he says. "My obligation is to my daughter, Princess Mahnaz, whom I love very much. She is 16, and she is coming to America to college next year."

Showering acquaintances with caviar, champagne and roses, Zahedi is sometimes baffled to discover that Americans can be put off by his gifts. In a typically overwhelming gesture, Zahedi once offered a photographer the expensive watch off his wrist because the man gave him a lift when the embassy limousine failed to show up.

The ambassador is one of the few Washington diplomats to remain in public contact with former President Nixon. "Whenever I go to California I go to San Clemente to pay my respects," he says. "And if it's Christmas or Easter I will send him flowers or caviar or chocolates. Whoever becomes President of the U.S. I have to respect. If that person is out of office, well, we have a custom in our country. We don't forget our friends."