Pippa Middleton already has two more books planned to come after this week’s launch of Celebrate: A Year Of British Festivities For Families And Friends.

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One is about planning weddings on a shoe-string budget and a third dedicated to throwing children’s parties.

A source told the website MailOnline: “Pippa has wanted to organise weddings ever since she was a little girl.

“It’s not something she simply thought about after helping to organise [her sister’s] wedding, although clearly having such a high-profile wedding under her belt will help with business.”

It is believed Pippa has signed a £400,000 deal with publisher Michael Joseph, an offshoot of Penguin, who won a bidding war to sign her in the aftermath of last year’s Royal Wedding between Duchess Kate Middleton and Prince William.

She was also determined to write the book entirely on her own.

A source said: “She was offered a host of ghost writers, but said no to them all.”

Celebrate makes no mention of her famous sister or her husband, but there will be a huge party to mark its launch and Pippa is set to embark on a tour and book signing.

The source added: “As well as a serialisation, plans are under way for her to do several book signings as well as a stock signing.

“Pippa is hugely proud of the book and is looking forward to it immensely.”