The late movie mogul Darryl F. Zanuck will make a cameo appearance as star witness at the long-awaited probate trial that pits Zanuck's three children against his mistress in a battle over his $3 million estate.

Zanuck will appear in a videotaped interview done the year before he died. A lawyer defending the three children said the tape will prove Zanuck was competent when he threw out a will that made Genevieve Gillaizeau a principal heir, with only $100,000 to his two daughters and nothing to his son.

That will, drawn up in 1973, lasted only six months before Zanuck wrote another restoring his son as an heir, and making no mention of Gillaizeau, who is now an art dealer in New York.

A nine-woman, three-man California Superior Court jury is expected to evaluate the claim of Gillaizeau that Zanuck would not have left her out of the will unless mentally incompetent or pressured by his children.

Zanuck, cofounder of 20th Century-Fox Studios, died three years ago at the age of 77. Gillaizeau, 36, met Zanuck in Paris when she was a 19-year-old aspiring actress.

Washington-area celebrities and tennis stars will battle the net this Saturday to raise money for the Georgetown University Women's Tennis Scholarship Fund.

"This is a first annual benefit for the scholarship fund to attract top-level scholar/athletes to Georgetown's women's tennis team," said Leslie Yerman, benefit coordinator.

The exhibition matches/cocktail party at the university's Yates Field House will feature Attorney General William French Smith, former secretary of state Alexander Haig Jr., Ethel Kennedy, tennis pro Pam Shriver and humorist Art Buchwald in mixed doubles.

Actress Elizabeth Taylor, who has been plagued with injuries ever since arriving in the Middle East last week, has canceled her scheduled trip into Lebanon.

According to Reuter news service, Taylor was expected in Beirut to meet Lebanese President Amin Gemayel and the commander of the right-wing Christian militias known as the "Lebanese Forces." However, the actress will return to the United States within two days for treatment of her injured leg, said her spokesman.

"It's enough," the spokesman said. "She's going to do permanent damage to herself if she doesn't take care of her leg."

Taylor ruptured two ligaments in her left leg Saturday when her limousine skidded on a rain-slick highway into an escort car. Last Thursday, the film star was taken to the hospital for tests after fainting in the desert. And since these episodes, Taylor has been limping and wearing a neck brace.

"The doctors here have been wonderful, but the best thing is to get her to her doctors," the spokesman added. "The doctors say the leg has to be straightened in surgery and put into a cast for five or six weeks."

Taylor arrived in Israel on a trip that included visits with Prime Minister Menachem Begin, Defense Minister Ariel Sharon and First Lady Ofira Navon. Because of her public support of Israel, the 21-member Arab League, of which Lebanon is a member, has blacklisted her.

Borrrrrring!!!! . . .

Former president Gerald Ford and comedian Don Rickles topped the "Ten Dullest Americans" list yesterday compiled by the International Dull Men's Club.

J.D. Stewart, head of the 2-year-old club, said he took time out from one of his favorite dull pastimes, snorting lime Jell-O, to create the list.

Among the dullest were:

Phyllis Schlafly; Walter Mondale, Fred (Mr.) Rogers ("Even kids find him boring," said Stewart); and the National Football League players' union.

Stewart's organization accepts only those people who don't conform to the norm; its entertainment slogan is "In Vinum Veritas." Or, "In generic beer there is truth."

Boston Mayor Kevin H. White, admitted to Massachusetts General Hospital Wednesday complaining of fatigue, was released yesterday after doctors pronounced him in good condition.

Spokesman George Regan said White was released in the morning after routine tests proved "normal." ------

Actor David Soul may get by without a wife-abuse conviction record if Los Angeles probation officials decide to place him in a diversion program for first offenders.

Municipal Court Judge Timothy England referred Soul's case to the probation department Tuesday after interviewing Soul's wife, Patricia, said Deputy City Attorney Susan Kaplan.

Kaplan said the actor's wife wanted to drop charges against her husband, who pleaded innocent to misdemeanor counts of battery and wife abuse, according to the Associated Press.

Soul played police detective Ken Hutchinson on the TV series "Starsky and Hutch." The alleged dispute between the actor and his wife occurred Oct. 25 at their Bel-Air home. Kaplan said Patricia Soul's face was bruised.

Presidential hopeful Sen. Gary Hart (D-Colo.) has reconciled for a second time with his wife of nearly 25 years.

Hart, who is expected to announce his candidacy for the 1984 Democratic presidential nomination soon, moved back into the couple's Bethesda home, said press secretary Kathy Bushkin.

Bushkin said the Harts have appeared together in public since November, but "weren't ready" to announce their reunion until now. She added the reconciliation was not politically motivated.

A columnist for the Minneapolis Star and Tribune has been suspended for a week without pay for helping Gov. Rudy Perpich write his inaugural address.

Jim Klobuchar also was restricted from writing about state government for an indefinite period, the newspaper said yesterday.

The columnist also was suspended in 1981 from his duties at the former Minneapolis Star for 10 days after he was accused of fabricating a quote in a column about a Minnesota Vikings game.

Klobuchar said he helped write the speech "as an act of friendship" to the governor," and added, "In retrospect, it was not a wise thing to do."

Environmental Protection Agency Administrator Anne Gorsuch should be released from the hospital in a few days, EPA officials said yesterday.

Gorsuch was admitted to George Washington University Hospital Monday night. EPA spokesman Byron Nelson said Gorsuch was admitted for tests and observation, but he refused to disclose the nature of her illness.

However, sources at the EPA, who asked not to be identified, said Gorsuch was admitted for what was thought to be kidney stones.

"Surgery is not going to be necessary and she is going to be out in a few days," said one source.

Singer Connie Francis yesterday urged Nevada legislators to toughen criminal laws and pass legislation to aid victims of violent crimes.

Francis, who was raped in a New York motel in 1974, said she is on a "state-by-state" campaign for tougher anticrime and victim rights legislation.

"I'm doing it on my own when I should be out singing and making a living," she told the legislators. "I'm going to take this to the people . . . "

Francis called for mandatory sentences for people convicted of violent crimes and the elimination of insanity and diminished capacity defenses. She also proposed a victim's impact statement for judges to consider during sentencing.

"The people are fed up with rhetoric, they're fed up with speeches that mean nothing," she said. "Many of you people talk a lot but don't make any sense."

Archeologists said yesterday in Cedar Park, Tex., that a 9,000-year-old human skeleton, one of the oldest found in the United States, was that of a young woman who was probably about 20 when she died.

The find excited scientists because so little is known about human history during that period. The dig, which started last January and expected to last another year, is being conducted before construction begins on a new highway about 18 miles northwest of Austin.

Workers were about halfway through unearthing the ancient skeleton yesterday.

"It's one of a kind. There's never been anything like this found before," said Frank Weir, director of archeological studies for the Texas Highway Department.

Weir said if carbon dating proves the estimated age to be correct, "that would put it back before Pharaoh, Moses, the whole bit, back at a time when there was no civilization to speak of. People were still hunters and gatherers."