Carole and Michael Middleton
Carole and Michael Middleton arrive at The Lindo Wing to visit their daughter Catherine, Duchess Of Cambridge and her newborn son on July 23, 2013 in London. Getty Images/Peter Macdiarmid

Kate Middleton's parents are in hot water for a controversial product.

Carole and Michael Middleton own Party Pieces website that sells decors, costumes and fun items for every occasion. According to Mirror, the store is selling a controversial item that the publication dubbed as "zombie Princess Diana" costume. It features a white princess gown covered in blood. The children's outfit is named "Zombie Sleeping Princess" on the site and is retailed at $14.32.

"This not so pretty princess costume features a blood-drenched pink silky dress with a jagged skirt," the description read. "The top includes a gruesome print of the poor zombie princesses ribcage and organs. This princess will be the scariest princess at any Halloween party."

The item is available in two sizes - medium for children age between 7 and 9, and small for little girls aged 4 to 6.

However, this did not sit well with Princess Diana's late friend Simone Simmons and Majesty magazine editor-in-chief Ingrid Seward. Both find the item sick and inappropriate.

"This is sicker than sick," Simmons said. "I hope people boycott this site."

She added that the costume was "warped and twisted." She also accused the Middleton's company as "scraping the barrel."

"This is in very poor taste," Seward added.

Carole and Michael also sold wedding decors ahead of Prince Harry and Meghan Markle's wedding. The union of the Duke and Duchess of Sussex's was deemed as a national celebration, so the website stocked up on everything from Union Jack flats, banner, bowler hat, fabric waving flags, confetti and more.

"Complete the look with this fun Union Jack Bowler Hat. Ideal for national celebrations, you can show off your British style with this hilarious hat. Great for taking some funny photos and showing off your national pride!" the description of the Union Jack bowler hat read.

In August, the website was accused of cashing in on Markle after they advertise a banner that uses the name of the new duchess except that it was spelled without an "h." At that time, the former "Suits" star was about to celebrate her 37th birthday.

The colorful banner can be personalized with the celebrant's name and age. For their promotion, the company features a banner with a message that read: "Happy 18th Birthday Megan."