The Duchess of Cambridge seems to be getting enough of her sister's socially-open ways. In fact, Kate is afraid her sister might embarrass her during Pippa's upcoming solo US tour.

Kate Middleton's younger sister, Pippa, is set to tour around the United States to promote her party-planning book entitled, 'Celebrate.' Although this might cause excessive amounts of excitements for both Kate and Pippa, the Duchess is somehow petrified that her younger, vocally reckless sister might say something that could embarrass her and the Royal Family.

"Pippa's been summoned for a crisis meeting. It's been decided she needs more protection." says a source to Now Magazine.

It has also been reported that Pippa refuses to take any schooling or media lessons from the Buckingham palace in preparation for her tour. Because of this, Kate is afraid that Pippa might comment on the unfortunate topless photo scandal that haunted the Duchess last month.

"Kate's personally overseeing it and has asked Pippa to agree to some intensive lessons in dealing with intrusion; what to say, what to wear - the lot." added the source.

Pippa will start her US tour later this month, and will visit various states to read excerpts from her book. Celebrate is

Also read:

Kate Middleton Gives Reese Witherspoon Union Jack Onesie As Gift [PHOTOS]

Kate Middleton's Confidence Boosted after Topless Photos; Anorexic Attitude? [SLIDESHOW]