BLACK Caviar's groupie army is on the move. Thousands of Australians are following the mare to Royal Ascot to witness her historic run firsthand on Saturday week.

''A huge number of people are going who wouldn't normally be involved in this sort of travel,'' said Peter Harney, managing director of Brisbane-based racing itinerary specialist Ambassador Travel.

''We've had other horses go across before; Takeover Target, Starspangledbanner … but nothing compares to this. Black Caviar's captured imaginations. It's the biggest phenomenon of people following one horse I've ever seen.''

JANICE BREEN BURNS reports in the SYDNEY MORNING HERALD that Mr Harney estimated up to 3000 Australians were directly Ascot-bound or planning hook-turns in their travel itineraries to take in Black Caviar's Ascot dash before resuming their trips. ''It's hard to say how many, but definitely thousands will be there,'' he said.

Virginia Allen's ensemble matches Black Caviar's silk colours. Photo: Getty Images

More than 350 Victoria Racing Club members have registered plans to use their reciprocal membership rights at Royal Ascot. ''Compare this with the 94 members who applied last year,'' says Julian Sullivan, executive general manager, club services, ''and the impact of this once-in-a-lifetime horse becomes clear.''

Mount Martha racing enthusiast Virginia Allen was so thrilled about her first trip to Royal Ascot on such a historic occasion, she commissioned an ensemble in Black Caviar's salmon and black polka-dot silk colours. ''It's just so exciting,'' she said. ''I love dressing up. I love horses. I couldn't resist the opportunity to do something quite special.''

Yesterday, at the Windsor Hotel, Mrs Allen met her milliner Kim Fletcher and couturier Jan Nico for a final check of her outfit. It's a process ignored at your own peril. ''The dress code is very strict,'' Ms Fletcher said. ''You must have a four-inch base on your hat, dress straps an inch wide, no string straps unless you're wearing a jacket.'' The code also ''kindly reminds ladies'' that midriffs must be covered and hemlines fall to slightly above the knees or longer.

Yesterday, Ms Nico carefully checked that her meticulously coutured shot-silk sleeveless dress for Mrs Allen, with its inch-wide straps, knee-length pleated skirt and fitted polka-dot mesh jacket with edge-to-edge fastening, passed muster. It did. As for the hat, for decades the ladies of Melbourne have commissioned Ms Fletcher's hats for Royal Ascot and she knows the rules.

But this year one detail made an extraordinary difference. ''Black Caviar,'' she said. ''Any other year, I'd do three, maybe four, hats for Ascot but, I just counted how many I've made this time: 35. It's that horse.''

STORY SOURCE: SYDNEY MORNING HERALD, FAIRFAX MEDIA GROUP,