SOME SAY the reason Americans get so excited when British royalty deign to visit our humble shores is that we have none of our own.

But anyone who believes that wasn't on the Avenue of the Arts Saturday night. Although most didn't break out their tiaras, Philly's answer to the so-called upper crust was out in force, enjoying one of the high points of the social season, the Academy of Music's Anniversary Concert and Ball.

At this annual gathering, which I understand has made at least small gains in terms of being diverse, concertgoers "promenade" along Broad Street in ball gowns that cost as much as a year's college tuition. Their escorts don white ties and tails. Some even go the extra step of adding dramatic black capes and white gloves. One dapper fellow I spotted Saturday managed to sport a top hat without looking the least bit silly. (Speaking of outerwear, the coat check should have been called fur check, considering all the minks, sables and other expensive skins crammed onto the racks.)

For me, it was a rare peek into an exclusive world, one populated by the uberwealthy, such as Dorrance "DoDo" Hamilton, the Campbell Soup heiress; philanthropists Raymond G. and Ruth Perelman; Caroline and Sidney Kimmel, chair and founder of Jones Apparel Group; and Jane and Leonard Korman (Korman Communities).

My entree to this glamorous night began with being handed my media credentials and assigned my own personal escort. (Translation: babysitter.) Polite and perky, she escorted a photographer and me into the presidential reception which, once you got past all the waiters with their trays of Veuve Clicquot and tables loaded with caviar, sushi, and jumbo shrimp, was like so many other upscale affairs.

The people-watching, though, was exceptional. But after seeing so many sequins and chiffon, it was hard to be overly impressed by some of the fashion - that is unless you don't count Caroline Kimmel (as in the Kimmel Center for the Performing Arts), who was dazzling in a navy-blue, skin-tight, mermaid-style couture gown complete with a heavy diamond-and-sapphire necklace with matching earrings. Same thing with Noele Wein of Glad-wyne and Palm Beach, who made a grand entrance in a blue and gray Oscar de la Renta ball gown with a voluminous skirt and train from Neiman Marcus and opera-length gloves. A custom-made, cream-colored fox stole hung casually over her shoulder.

After that reception, as well as an even more exclusive one attended by Prince Charles and wife Camilla that I wasn't privy to, the concert portion of the evening got under way. From the cheap seats way at the top of the hall where members of the media were placed, I could make out TRH - The Royal Highness, as Prince Charles is called - and Camilla in a box with Leonore Annenberg, widow of Walter H. Annenberg.

I tried to shake thoughts about the late Princess Diana out of my head and instead look for other famous faces. (Note to self: Next time, bring binoculars.) Mostly, though, it was a blur, although I could make out Mayor Street in a box across from the royals, and U.S. Rep. Chaka Fattah and NBC-10 news anchor Renee Chenault-Fattah directly overhead.

Emceed by former NBC News anchor Tom Brokaw, Saturday night's concert was a tribute to the "grand old lady of Locust Street," as the Academy is called, and all the operas, concerts by the Philadelphia Orchestra, and other productions it has hosted over the last 150 years. Opera star Angela Brown, a last-minute fill-in for vocalist Deborah Voigt, who hurt her back, was a crowd-pleaser, as was actor John Lithgow, who, aided by a box of props, performed a light-hearted medley of show tunes.

But it was rocker Rod Stewart, in a Michael Jackson-style military jacket and tight-fitting black trousers, who got the audience energized with his classic "Maggie May." The show ended in a blaze of silver confetti as he belted out "Forever Young" as a tribute to the Academy.

Afterward, concertgoers poured out onto Broad Street, where Mummers serenaded them as they made their way to dinner and a ball at the Park Hyatt at the Bellevue. I could go on and on about what went on in the multiple ballrooms, including one in a tent in the middle of South Broad Street.

But, alas, like Cinderella, my time at the ball was about to expire. The media weren't invited to dinner, so as the partygoers sat down to beef tenderloin, the wicked stepmother - I mean, my escort - kept me reminded that my evening was coming to an end. By then, my sandals were cutting into my feet anyway. So, with her trailing behind, I headed onto Broad Street. *