Pippa Middleton is not happy.

According to the UK's Sunday Times, Kate's younger sister is threatening to sue a popular Twitter account and parody book that has been enjoying great success at her expense.

Middleton has reportedly launched legal action against Mat Morrisroe and Suzanne Azzopardi, the creators of @Pippatips, a spoof Twitter account which lampoons the 29-year-old socialite by sharing comically basic party planning and fashion "tips" with its 50,000-plus followers:

Capitalizing on their Twitter success, Morrisroe and Azzopardi took another swipe at Middleton in June, publishing a parody book entitled When One Is Expecting: A Posh Person's Guide to Pregnancy and Parenting. As MSN notes, the spoof guide has since surpassed Middleton's book Celebrate in Amazon sales in the UK.

Not that it was too hard. We still haven't forgotten the bomb that was Celebrate, which not only sold shockingly few copies but also made Pips the butt of many jokes poking fun at her lackluster advice.

"Could it be more basic? Why not try roasting a turkey for Christmas or lighting small candles on a cake to celebrate a birthday? Hey, here’s another crazeee idea -- what about making pancakes for Pancake Day?" wrote the Daily Mail's Jan Moir last year in her review of the book.

Despite the barrage of criticism, plucky Pips initially took it all in stride, even laughing off the success of @Pippatips. "It’s all good fun, I know, and I realize that authors ought to take criticism on the chin," she wrote in an essay for the Spectator in December.

Her tune, however, seems to have changed dramatically. According to the Times, Middleton's lawyers have demanded that Morrisroe's and Azzopardi's be pulled and that their Twitter account be deleted. Maybe she's cracking down now that she's a fancy Vanity Fair editor?

@Pippatips has been silent since June 14.

Happier times?

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  • May 2013 -- clubbing with Nico Jackson

    Pips shows off those enviable stems in an LBD.

  • July 2015 -- Wimbledon

    Pippa and Nico show off their crisp summer wardrobes while taking in some tennis.

  • March 2013 -- Cheltenham Festival

    Pippa walks out in an outfit that <a href="http://www.huffingtonpost.com/2013/03/14/pippa-middleton-fur-hat_n_2875816.html?utm_hp_ref=pippa-middleton" target="_blank">totally channels Kate:</a> a Katherine Hooker coat and a fur hat.

  • March 2013

    Usually heavily made-up, Pippa <a href="http://www.huffingtonpost.com/2013/03/08/pippa-middleton-no-makeup-photos_n_2838349.html?utm_hp_ref=pippa-middleton" target="_blank">steps out for lunch with her mother with hardly any makeup on</a>.

  • December 2012 -- Holland

    She wears a Beulah London electric purple peplumed sheath with matching pumps and nude tights to <a href="http://www.huffingtonpost.com/2012/12/11/pippa-middleton-book-launch-holland-style-photos-pictures_n_2278636.html?utm_hp_ref=pippa-middleton" target="_blank">promote her book</a>, "Celebrate: A Year of Festivities for Family and Friends."

  • December 2012

    Pippa <a href="http://www.huffingtonpost.com/2012/12/10/pippa-middleton-sneakers-photos_n_2271869.html?utm_hp_ref=pippa-middleton" target="_blank">dresses herself down and looks super-edgy</a> in Amandine sneakers from Sandro. We love it!

  • October 2012 -- Visiting a Botox Spa

    Pippa <a href="http://www.huffingtonpost.com/2012/10/17/pippa-middleton-london-photos-botox_n_1974057.html?utm_hp_ref=pippa-middleton" target="_blank">pays a visit to Santi</a>, a spa that focuses on "aesthetic therapies to rejuvenate the skin."

  • October 2012

    Pippa <a href="http://www.huffingtonpost.com/2012/10/17/pippa-middleton-photos-pictures-style-fashion_n_1973028.html?utm_hp_ref=pippa-middleton" target="_blank">proves she is a style risk-taker</a> (by royal standards) by stepping out in awesome casual outfits that prove she knows how to perfect the art of street-style.

  • September 2012 -- New York

    She <a href="http://www.huffingtonpost.com/2012/09/05/pippa-middleton-new-york-apartments_n_1858241.html?utm_hp_ref=pippa-middleton" target="_blank">looks for apartment in New York City</a> sporting cropped red pants, a blue blouse and white sunglasses.

  • July 2012

    She <a href="http://www.huffingtonpost.com/2012/07/19/pippa-middleton-starbucks_n_1686792.html?utm_hp_ref=pippa-middleton" target="_blank">goes for a morning Starbucks run</a> in a perfect summer dress.

  • July 2012

    Pippa wears an Alice Temperley dress with a dramatic black fascinator for the wedding of Alice St. John Webster and Gerald Avenel. <a href="http://www.huffingtonpost.com/2012/07/02/pippa-middleton-wedding-dress_n_1644506.html?utm_hp_ref=pippa-middleton" target="_blank">She was dateless.</a>

  • June 1012 -- Wimbledon

    She <a href="http://www.huffingtonpost.com/2012/06/28/pippa-middleton-wimbledon_n_1634100.html?utm_hp_ref=pippa-middleton#slide=1156959" target="_blank">keeps it perfectly prim and proper </a>in a navy Orla Kiely dress and buttoned-up print jacket. She attended the match with then-boyfriend Alex Loudon.

  • June 2012

    Here she is with her brother, James, at the Diamond Jubilee Pageant on the River Thames in London.

  • April 2012 -- Paris

    Here she is <a href="http://www.huffingtonpost.com/2012/04/15/pippa-middleton-paris_n_1426670.html?utm_hp_ref=pippa-middleton" target="_blank">dressed in a costume for her friend Arthur De Soultrait's birthday party.</a> She keeps it fashionable with an edgy black leather jacket over the ridiculous get-up.

  • March 2012

    She looks exuberant and beautiful as she crosses the finish line at the 88th Vasaloppet cross country ski marathon in Mora.

  • July 2011

    She knows how to rock a summer dress. Here she is attending the semifinals at Wimbledon.

  • October 2011

    She looks stunning in a silk floor-length gown at All Saints Party in aid for Too Many Women, supporting breast cancer research in Richmond, UK.

  • June 2011

    Pippa shows her competitive side as she crosses the finish line at the GE Blemheim Triathlon at Blenheim Palace.

  • May 2011

    Pippa shows how to wear double denim as she leaves an office in Kensington.

  • May 2011

    She displays the best balance of sophistication and coolness in her street style.

  • April 2011 -- The Royal Wedding

    The Alexander McQueen dress that shook the world: Pippa shows off her svelte body and steps into the limelight at Kate and William's wedding at Westminster Abbey.

  • April 2011

    After she solidified her place as a sex-symbol by wearing her form-fitting dress at Kate's wedding, Pippa shows she can rock a professional blazer but makes it look casual-cool with jeans.

  • February 2011

    She keeps English wedding fashion edgy and unpredictable with bright colors at the wedding service of Lady Katie Percy.

  • November 2008 -- Somerset House Ice Rink

    Pippa ice skates at the VIP opening of the Somerset House Ice Rink in London.

  • September 2008 -- London

    Pippa knows how to party. Here she is attending the Day-Glo Midnight Roller Disco at The Renaissance Rooms.

  • June 2008 -- London

    Pippa attends the Sotheby's Summer Party in a cute coral frock.

  • November 2007 -- London

    Here she is attending the book launch party of "Time to Reflect" by Alistair Morrison in an extremely fashion-forward black lace dress.

  • Pippa Middleton Spotted Kissing New Boyfriend On Ski Trip

    Pippa Middleton apparently kissed her new boyfriend on the slopes of St Moritz after enduring a gruelling cross-country ski marathon.

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