Pippa and Kate Middleton
Catherine, Duchess of Cambridge (right), with her sister Pippa Middleton at the Wimbledon Tennis Championships in London, July 8, 2012. REUTERS

Kate Middleton is concerned that her sister Pippa Middleton’s future brother-in-law Spencer Matthews may divulge family secrets in a bid to gain popularity, Life & Style magazine reported Wednesday. Spencer is a reality television star who appears in British reality series “Made in Chelsea.”

“She [Kate] is horrified about Spencer being Pippa’s brother-in-law,” a source told Life & Style.

“The last thing [Kate] wants is for [Prince] William’s family to turn against her because of Spencer’s actions,” another source told the magazine.

Late last month, Pippa and James Mathews confirmed that they were engaged. Following this, speculations over her wedding began and some media reports debated whether the ceremony would be as striking as that for the Duchess of Cambridge.

Pippa is likely to wed at her parents’ house in Berkshire in southeast England. A source told Britain's Bella magazine that the Middletons will “most likely host it in a marquee in their garden.”

In Touch Weekly recently claimed that Kate and Pippa are feuding after the latter’s engagement. The report said Pippa is “fed up with Kate’s judgmental attitude.”

“During a heated discussion, Kate expressed how unhappy she is because of James ‘uncouth’ family connections. She believes they will try to cash in on the royal family,” a source told the magazine. “Kate goes out of her way to portray herself as the perfect princess and is petrified the fame-hungry Pippa is going to ruin everything.”

However, Gossip Cop debunked the report.