She smiled when they suggested the other night on TV that long-lost cousins might be coming out of the woodwork for her American debut. Did she think they were kidding?

Princess Diana, meet cousin Reggie.

Now, now, don't get upset. He's a mere "fourth or fifth cousin" by his calculation, and he's not trying to muscle in on the royal shindig.

"We're very proud of the fact we're related to Lady Diana, but one is not that presumptuous," says Reginald Cecil Ponsonby Mitchell, 60, owner of a popular British pub here. "If one is so blessed, one is grateful."

Nor is he pitching for invitations for three grown children (distant cousins, too) who live within a bagpipe's carry of the White House.

"It's not the sort of thing one goes looking for," he says. "Famous people have lots of long-lost cousins."

Indeed. So, the owner of Reggie's British Pub downtown is celebrating his royal cousin's arrival in his own reserved way. He's put a large portrait of Charles and Diana in his pub window, laced with bunting. A TV over the oak bar is tuned to breaking pomp. And a royal bash, for anyone not invited to the real thing, is on for Wednesday.

Tankards of Newcastle and Whitbreads ale will flow, along with a new concoction whipped up to honor his cuz: Rum Diana, $1.95. "It's actually quite good," grins Reggie. "Just tried the first batch."

He parades past etchings of royal hussars on the wall, chatting up his connections in a clipped British accent. He halts by a photo of himself with Prince Charles during a 1977 visit to Atlanta.

He certainly looks the part of royal cousin in his double-breasted blazer, blue club tie and white handlebar mustache, evoking a clubby Michael Caine in a burnished wood domain. No more humiliating days at the hands of drunk sports fans who wandered in hunting another Reggie named Jackson.

Now patrons include Ted Turner, who stopped by Friday for soup and a sandwich en route to the $10,000-a-couple Palm Beach gala for the royals, and die-hard Diana junkies like John O'Callahan, 27, a local charity fundraiser who dropped in to say, hear, hear.

"They've got the perfect, boring life," O'Callahan said, toasting the arrival with friends chez Reggie's. "They don't have to work. They have status."

"I'd marry her," said Paul Spitznagel, 23, a bank loan officer who hosted friends with champagne and strawberries when the royal couple tied the knot. Colleague Elaine Oastler, 24, another bank officer, puzzled over Diana's appeal.

"It must be the jewelry," she said. "I read in Newsweek she nags her husband. She's turning him into a vegetarian."

Apart from his royal connections, Reggie has led a charmed life. In 1940, he shipped out to America on the last ship of evacuees allowed to leave Britain before wolf packs of German U-boats shut down the sea lanes. He was 14. Three years later, he was home, playing neighborhood warden during air raids. One night, his sister urged him to wear his helmet as he climbed out a window to scout damage from a German bombing raid. Seconds later he was blown from his perch, shrapnel embedded in his tin hat. He escaped without a scratch.

Soon he was off to the Punjab frontier as a royal marine. He spent a year rounding up POWs, then came the end of the war and he cashed out, enrolling at the University of Georgia in Athens to study journalism. He roamed the country as a free-lance writer, actor, lumberjack and ranch hand.

He married, played a Scotland Yard detective in a British film, hustled men's fashions for an Atlanta department store and, in 1973, opened a British pub here, adding a Reggie's later in Norfolk.

One son, a Georgetown University grad, is hunting work in Washington after a stint on the Mondale campaign. Two daughters live in suburban Virginia, their glory days hailed on Daddy's wall.

Reggie halts solemnly before a portrait of Sir William Ponsonby, Union brigade commander killed at Waterloo. "His men did a fabulous charge to avenge his death," beams Reggie.

Another ancestor, Lord Cornwallis, was also a big loser, and every July 4 Reggie hosts a "Grand Loser's Party" to salute his defeat at the hands of George Washington.

There are photos of royal hunts, the royal family, Reggie as a royal marine in Burma, Reggie as director of the British Mens Wear Guild posing with the queen, Sir Winston Churchill -- another forebear, he said.

One regal-looking chap hangs near a green velour banquette, next to a British beer sign. That would be the first earl of Spencer. Before she was catapulted to Cinderella princess of Wales, Diana went by Lady Diana Frances Spencer. Her daddy is the present earl of Spencer.

Reggie's never met them, but imagines she's got "lots of fourth and fifth cousins like me. It's nice to know you've got a common ancestor."

They go back to the early 17th century, when John Churchill (Reggie's Sir Winston connection), the first duke of Marlborough, had a son and two daughters. The son died in his early twenties, and by royal decree, the title was allowed to pass to the female line. Voila! An instant duchess of Marlborough, who married a Spencer.

On down the line, Lady Henrietta Spencer married the third earl of Bessborough, whose family name was Ponsonby, bringing Reggie's clan into the fold.

"She married Lord Melbourne before he fell madly in love with Lord Byron," says Reggie. "But that's another story."