For $2,500, a guest at tonight's Royal Gala gets to watch Diana eat. An additional thousand buys a handshake and a hello.

Her Royal Highness, the Princess of Wales -- Di to hoi polloi -- lands in Washington this afternoon for a solo appearance at an exclusive gala tonight and a visit to Grandma's House, a home for children with AIDS, before zipping back to London tomorrow afternoon.

"You have to be an AIDS patient or have 10 million dollars to meet her in America," said Andrew Morton, author of an upcoming profile of the princess, "Diana's Diary." "There's no way for the middle class to see her. It's not the embassy's fault; organizers hijack the royals for their rich and powerful friends."

"Rich" is the operative word tonight. The evening is expected to raise more than $500,000; half of the proceeds will go to the London City Ballet, of which Diana is a patron, and the other half will benefit the Washington Ballet and Grandma's House.

Only 250 people, a relatively intimate number for a charity fund-raiser, will sweep into the Departmental Auditorium for the real draw of the night -- their date with Diana.

"She's a fairy tale come true," said Elizabeth Valk, publisher of People magazine, who sat with Diana (she has appeared on the cover of the magazine 43 times) at a fund-raiser in New York last year. "She personifies all those fantasies little girls have about being a princess. You just couldn't help but get caught up in it."

The gala is white-tie -- the most formal dress -- which calls for tails, elaborate gowns and the most expensive jewelry in the safe. Dom Perignon champagne will flow all night. The flowers are coming fresh from Holland, the caterers are flying in from London (serving filet of beef, green beans and fruit cup) and 500 gold-colored chairs are being imported from England to match the gold china and flatware. The guests will be greeted by 10 footmen dressed in 18th-century costumes and served by 100 waiters in gloves and tails.

The guest list is drawn primarily from American corporate and business leaders; few political types will attend the dinner, sponsored by Michael Ashcroft, honorary president of the London City Ballet. Ashcroft is president and chairman of ADT Ltd., an international security firm. British Ambassador Sir Antony Acland and Lady Jennifer Acland will be on hand, along with some of Washington's leading social lionesses including Evangeline Bruce, Lenore Annenberg, Pamela Harriman, Buffy Cafritz and Georgette Mosbacher.

Two large tents will be erected in the ballroom. The Silver Donors ($2,500) have to settle for trying to catch a glimpse of Diana during the dinner. The Gold Donors ($3,500) will be received by the princess.

"Obviously, those who pay it aren't going to be hurting," said Eric Levin, editor in chief of People magazine's just-released collector's edition "The Decade of Diana."

"I think they'll feel they got their money's worth," he said. "People who have spoken to her are unanimously enthralled."

Levin said she blends regal bearing with a "very American" quality. "She has the wholesome blond looks that could have come from the wheat fields of Kansas, she's effervescent and leggy enough to be a California girl, and yet sophisticated and elegant enough to be a New York woman."

Who happens to be married to the next king of England.

"The correct way to bow to a royal, by the way, is by the neck," said Levin. "Only servants or performers bow from the waist."

Diana herself is quite progressive; a handshake is okay with her when she comes to the United States.

Those who have spoken with the princess give her glowing reviews. Valk said that Diana took the time to speak to a number of people during the New York fund-raiser. "You didn't get the feeling she was doing you a favor," she said. "I was absolutely convinced she loved her job."

Valk said she's been asked about the evening "three times a week" for the past 18 months. Most of her conversation with Diana was off the record but she admitted they chatted about jet lag and Diana's hairdo.

"You know the British. They can say something like that and still sound dignified."