LONDON (Reuters) - Paparazzi favorite Pippa Middleton is already a global celebrity. Now the 29-year-old sister of the future British queen is aiming to become a global brand.

The woman whose appearance at the spectacular 2011 wedding between Kate Middleton and Prince William caused as much of a sensation as the bride herself has written a recipe and party planning book which hits the shelves this week.

"Celebrate: A Year of British Festivities for Families and Friends" has been praised and pilloried in equal measure ahead of its Thursday release, but, perhaps predictably, Middleton's introductory comments have dominated the headlines.

In them, she addresses her status as one of the world's most photographed individuals, and even tackles the topic many people most closely associate her with - her behind.

"It's a bit startling to achieve global recognition (if that's the right word) before the age of 30, on account of your sister, your brother-in-law and your bottom," she wrote with a candor that won admirers in the royalty-obsessed British press.

"One day I might be able to make sense of this. In the meantime I think it's fair to say that it has its upside and its downside." The upside could be the size of the book deal.

Penguin imprint Michael Joseph, which is publishing the 416-page glossy hardback in Britain, has declined to give details of the size of the agreement, although a spokeswoman said some media coverage of the book had bordered on fiction.

The widely reported, but unsourced, amount is 400,000 pounds ($640,000), a sum which to most unpublished authors would appear astronomic although such advances are not unheard of.

Lena Dunham, three years Middleton's junior and the American creator of HBO comedy "Girls", was paid more than $3.5 million for her first book, according to the New York Times.

NO INTERVIEWS

The Penguin spokeswoman did not confirm a Daily Mail report, also unsourced, that Middleton had signed up for more books, and added that one-on-one interviews to promote the publication were "never part of the plan".

The British media linked the decision to royal sensitivities over the likelihood that Middleton would be asked questions about the Duke and Duchess of Cambridge - the titles her royal brother-in-law and sister have now adopted.

The Middletons' relationship with the press has not been easy of late.

When Kate was photographed topless on holiday, the royal family sued the French magazine that published images which the palace described as a "grotesque" breach of privacy.

A tabloid picture editor estimated Pippa was photographed by paparazzi up to 400 times a day, underlining how important the sisters have become for the celebrity and tabloid press.

As well as selling newspapers and magazines and driving internet traffic, they are also considered major trend-setters who can sell outfits faster than just about anyone.

Now Pippa hopes to turn her experience working for her parents' party planning company to good commercial use.

Early reaction to Celebration, excerpts of which appeared in the Mail on Sunday, has ranged from the snide to the supportive.

The Daily Mail's Jan Moir could barely hide her skepticism.

"Critics might wonder what Pippa Middleton really knows about entertaining - particularly as she looks like a girl who has spent her entire life being entertained," she wrote.

"From the moment she appeared in butter satin at her sister's wedding, Pippa has struck absolutely no one as the kind of girl you would always find in the kitchen at parties."

But Bryony Gordon takes up her defense in the Daily Telegraph, which, like the Mail, is generally pro-royal.

While conceding that "the abiding feeling generated by Celebrate should be one of nausea," she praises Middleton for avoiding obvious exploitation of her royal connections.

Of "oddly comforting" recipes, Gordon adds: "If the world's most famous bottom can make blackberry butter, then I can too."