Pippa Middleton, the Duchess of Cambridge's younger sister, was dropped by her literary agent David Godwin who helped her launch her party-planning book "Celebrate."

The news were first reported by UK's Daily Mail on Thursday which claimed that a strong reason for the termination followed by poor sales of the book.

"I am very sorry it has happened, but yes, it is true. I no longer represent Pippa and I wish her every good luck," Godwin told the Daily Mail.

With the help of Godwin, Middleton landed a deal with book publisher Penguin for which she was paid $400,000 in advance from publisher Michael Joseph.

Middleton published her book "Celebrate: A Yer of British Festivities for Families and Frieds" in October but was struck with little favorable reviews and sales.

The book reportedly sold only 2,000 copies on its first week and in December, U.K. bookseller WH Smith reduced the book's price 75 percent to try to boost the sales.

A parody Twitter account called @PippaTips was inspired by the book mocking her over simplistic advice such as her main tip to celebrate Christmas: "because of their size, turkeys are perfect for feeding larger gatherings."

Among other things, critics blasted her ideas for serving ice at parties "make batches of your own and store in freezer bags." and for banal descriptions such as telling people how to hold a sack race, according to UK's The Telegraph.