Transworld launched Jilly Cooper's new equine-themed "blockbuster" novel Mount! (Bantam) at a star-studded bash at the Mandarin Oriental in London's Knightsbridge.
The event, attended by TV and media personalities Paul O'Grady, Rachel Johnson and Tim Wonnacott, also hosted a real life horse, along with trainers, jockeys, stable staff and stud owners, and racing pundit John McCririck.
A white stallion grazed the lawn of the luxury London hotel at the party, to the delight of guests. According to Cooper, the horse was rescued from Spain where he was on route to Holland "bound for the meat market".
Cooper and guests including Paul O'Grady enjoyed the company of a white stallion at the launch
Addressing the room, Cooper thanked guests at the "heavenly party" and also laid to rest speculation about the man and inspiration behind Rupert Campbell-Black, revealing it was in fact "three charismatic, glamorous men" who inspired the character: Andrew Parker Bowles, the Earl of Suffolk Michael Howard and Rupert Lycett Green.
"All the Ruperts are here and I want to say they are all impeccably behaved. I made up bad behaviour," she said.
"I'm so grateful to Larry and everyone at Transworld. They are absolutely brilliant," she added. "I do think the message on the front cover is a bit arbitrary; it orders you all to 'Mount!' Jilly Cooper! You can form an orderly line, and shake my hand."
Larry Finlay, m.d. of Transworld, praised Cooper in a speech as a "dream of an author" and hailed her latest novel "a complete triumph". The book has been a number-one bestselling hardback novel for all the online retailers on pre-order ever since Cooper appeared on BBC Radio 4's "Desert Island Discs" at the end of July, according to Finlay.
He said: "[Rupert Campbell-Black] has got to be one of the most adored and self-refined creations, and from tomorrow hundreds of thousands of people will be going to bed with Rupert until the morning.
"It's been six years since we published Jilly's last number-one bestselling lovely Jump. And the nation is hungrier than ever for a return to Rutshire, and to the Chronicles, and to return to the clutches of Rupert.
"Event publishing is often a term overused by publishers. But the publication of a new Jilly Cooper blockbuster truly is an event."
He added: "Thank you for giving us such a brilliant read. I know it is going to fly from the nation's bookshops from tomorrow."
Transworld last month invited booksellers across the country to host their own "Jilly Cooper Night" tonight (8th September), on the book's publication date, providing special packs to retailers with all they need for "an evening of quizzes, games and lively book club discussion to welcome the dashing Rupert Campbell-Black back onto our bookshelves". Limited edition signed hardback proofs were also provided as prizes.
Cooper celebrated with her editors Bella Bosworth (left) and Linda Evans