The 'Keeping Up With the Kardashians' stars are the subjects of a lawsuit filed by Klauber Bros. Inc., who design two-dimensional artwork for the purpose of lace production and who claim the sisters have ripped off two of their very specific, copyrighted designs.

According to documents obtained by TMZ, Klauber claim that a piece in the Kylie Thong Panties line uses one of their designs, as does a slip from the Kylie + Kendall range.

The company has accused Kylie and Kendall's business of cashing in on their designs by selling their garments in Nordstrom and the online outlet Kylie Shop so are suing for all of the profits the pair have made from any designs allegedly using their lace.

Representatives for the sisters have yet to comment on the lawsuit.

Meanwhile, the pair's half-sister, Khloe Kardashian, recently confirmed Kendall and Kylie have "different contracts" for their family reality show to the one which she, Kim Kardashian West and Kourtney Kardashian had which stated they had to have "equal" input into 'Keeping Up With the Kardashians'.

The revelation came to light when Kim, 39, moaned about Kourtney, 40, not wanting to document her romantic relationships on the programme during an episode in December.

She said: "All of the days that Kourtney isn't filming, Khloé and I are picking up the slack and having to share more. Because if we're not sharing our lives, then what is the show?"

One fan questioned: "this ain't shade AT ALL but do Kendall and Kylie have different contracts now for #KUWTK? cos Kendall rarely films and Kylie isn't featured a whole lot?(sic)"

To which Khloe, 35, replied on Twitter: "Kendall and Kylie have different contracts.

"Kourt, Kim and I have an equal contract. (sic)"

'Keeping Up With the Kardashians' launched in 2007 and originally focused on the lives of Kim, Kourtney and Khloe as Kendall, 24, and Kylie, 22, were only 11 and 10 at the time.