Guests including Kate Moss and Bob Geldof have flown to India after Campbell organised extravagant celebrations for Russian boyfriend Vladimir Doronin in Jodhpur.
She hired out the huge fort that dominates the city, flying in Diana Ross for a live performance and booking a whole five-star hotel for accommodation.
Reports that a number of the 200 guests, who include the Duchess of York Sarah Ferguson, would play elephant polo were dismissed by Campbell in a statement issued by her spokesman.
Some animal rights campaigners believe the sport is cruel and had criticised Campbell for planning to hold a game, but she said she was "extremely upset" by the claims and that no polo was ever planned as part of the celebrations.
Colourful sofas, cushions and carpets were being laid out in courtyards inside the Mehrangarh Fort ahead of the party, with the fort's dramatic walls expected to be lit in pink and yellow lights.
A huge mock poster of Mr Doronin as James Bond and Campbell as a Bond girl was also on display at the venue as hundreds of workers rushed to complete last-minute preparations.
The Press Trust of India news agency said that 12 chartered planes had been laid on to bring in guests, who were chauffeured in vintage cars from the city's small airport to their rooms at the luxury Umaid Bhawan Palace hotel.
"We have provided them with 50 policemen and 50 home-guards, who will take care of the security arrangements outside the fort and from the airport," senior Rajasthan state police officer Rahul Prakash told PTI.
Campbell, 42, has been dating Mr Doronin since 2008 and the couple currently live together in Moscow.
They have a record of throwing elaborate parties for each other, with Mr Doronin hosting a major party for Campbell's 40th birthday on the French Riviera.