Photographs of Sen. Edward M. Kennedy at parties with curvaceous blondes raise eyebrows, and gossip columnists and political pundits were puzzled when Washington newspapers briefly printed just such a picture in March.

The mystery: Who was the glamorous woman pictured with Teddy at a White House dinner celebrating the signing of the Israeli-Egyptian peace agreements?

Suspicions grew when the photograph was replaced in The Washington Star's second edition by a shot of Kennedy alone. And in the third edition by a shot of Kennedy with the Rev. Msgr. Francis Lally of Boston. The Post printed a similar picture in an early edition but pulled it out because of space considerations.

"The Case of the Vanishing Blonde," read the headline in The Boston Globe. Her name did not appear on the official guest list provided to the press by the White House. Look magazine labeled the unknown woman "a party-crashing blond bombshell . . . an uninvited guest."

Now it can be told: Annie Davidson is a 24-year-old former Miss Australia who arrived at the White House with Kennedy and her date, millionaire Georgie developer and playboy Elliott Robinson, 43. She is amused by the flurry of press attention that greeted her appearance.

"They made such a big deal over nothing," Davidson told Washington Post reporter Art Harris at the fashionable Cloister Hotel in Sea Island, Ga. Along with boyfriend Robinson, Davidson divides her time between Sea Island and Aspen, Colo. When he vacations in Aspen, Kennedy sometimes skis Aiax Mountain with Robinson. The senator invited his bachelor friend to the White House event, and after drinks at Kennedy's office, the senator, Robinson and Davidson piled into Kennedy's 1973 Pontiac for a ride to the White House. Because Robinson had not replied to his invitation, his date's name was not on the White House guest list. And when Robinson answered press shouts of "Who are you and who is she ? with "My name is Elliott Robinson and this is my girlfriend, Annie Davidson," no one listened, he said.

"They're all asking who you are. I'm never going to hear the end of this," Davidson recalls Kennedy remarking to her.

The pop of flashbulbs is nothing new to Davidson, an easygoing 34-24-34 former model who appeared as Miss Australia in a Miss World competition in London. In America she modeled for major agencies including Nina Blanchard and Eileen Ford, though she says underneath her makeup, she has freckles. "I don't look at myself as pretty," she says. "I'm a black canvas. Put some paint on it and I can be whatever you want."

Nonetheless, she was asked to tout everything from Jeep Renegades to Mr. Pibb. She refused Playboy's invitation to disrobe between its covers.

Davidson met Robinson last December in Aspen. He was a south Georgia bon vivant who says he previously considered a two-night stand a long relationship. She was a world-weary model, ready for a rest. He started her jogging, she cooked his training meals for the Boston Marathon. He finished in 2:56. They've been together ever since.

"I'd love to be a housewife," she says, which is just as well because Robinson recently took her home to south Georgia to relax at his rambling beach house that comes complete with sauna and white Rolls Royce. And Teddy-watchers might be interested in Robinson's other reasons for taking Davidson back to Georgia: he wanted her to meet his mother. CAPTION: Picture 1, Edward M. Kennedy, At first . . . ; Picture 2, Edward M. Kennedy, And then . . . ; Picture 3, Sen. Kennedy and Msgr. Lally, And finally. The Washington Star; Picture 4, no caption, By Art Harris