Lt. Gov. John N. Dalton last week launched his Northern Virginia campaign for governor on the hemline of a famous film actress. Or did he?

That was the question many Virginia Republican leaders found themselves asking after Dalton - with the help of actress Elizabeth Taylor - raised a near-record $17,500 at a $50-a-head reception at Alexandria's Belle Haven County Club.

Not since President Gerald Ford visited the club in 1974 on behalf of then-Rep. Stanford E. Paris had so many of the region's Republicans turned out for such a costly fund-raiser. And never, former Republican Gov. Linwood Holton told the 350 guests, has the party appeared so unified, so early for a general election. The turnout, therefore, may have special significance this year.

Despite Dalton's cheery predictions that he can easily defeat Henry E. Howell or Andrew P. Miller, the Democratic candidates, most Republicans acknowledge that a Dalton victory will not come that easy. That's why many found themselves wondering about the significance of the turnout at Dalton's fund-raiser.

"John couldn't have done all this," said Del. Wyatt B. Durrette (R-Fairfax), looking about at the packed banquet room with a mixture of amazement and envy. Durette, who is running for the party's nomination for attorney general, credited the appearance of Miss Taylor, 45, and her husband, former Navy Secretary John Warner of Loudoun County, for the crush.

"You have to be honest - she is a draw," Durrette said.

A slightly different view came from Fairfax Board Chairman John F. Herrity, who said probably "90 per cent" of those at the club were the traditional, party-oriented Republican faithful of Northern Virginia.

"They're all true belivers," claimed State Sen. Wiley F. Mitchell (R-Alexandria). "You wouldn't be out here and shell out $50 otherwise," he said.

Neither Dalton nor his top aides seemed worried about what brought the crowd out. "If they're coming out to see Liz, then, they're going to see John, too," said aide Larry Murphy.

Whatever their motive, Dalton saw the evening as a major plus in a region where he - and most other Virginia political figures - suffer poor voter identification. "Virtually every one that came through that line said they would support me," Dalton said after two and a half hours shaking hands alongside Miss Taylor.

Miss Taylor's presence and the constant poppings of flash cameras around her troubled some of the party faithful. "They're all taking pictures of her," groused Fairfax precinct worker Susan Crummer. "This is John Dalton's show; he should be the star."

Dalton, of course, wasn't the only person seeking political office at the club last week. There was none other than Miss Taylor's current and sixth husband, a former college roommate of Holton and a man widely thought a likely candidate for the U.S. Senate seat Republican William L. Scott will vacate next year.

Warner, 49, whose graying hair was stylishly curled around the nape of his neck, quickly dismisses any suggestions that he and his wife of four months are campaigning themselves. "At this time, I'm working to strengthen the two party system," he said as he pulled Miss Taylor aside for a "head call" at the club.

But Warner freely admitted that within the next three months they will be making between 30 and 40 separate appearances around the state for "everybody from Gov. Dalton to delegate places."

Still, he says that he is hearing of "a growing interest" by Virginia Republicans in his political future. "They're not just interested in photographs, they're wishing us well," he said.

For the moment at least, that means that the Republicans won't have to sit back out of the public limelight while the state's Democrats attract all the attention with their June 14 primary. Dalton, for instance, served up notice that he will be in Northern Virginia so much in the next eight months "that you're going to think that I'm one of you."

Holton simply chuckled aloud when he was asked about all the sudden interest in the party's gatherings. "It's simply relegating the Democratic primary to the importance it deserves," he said.