Khloe Kardashian co-founded the denim label Good American. (Picture: Instagram)

Khloe Kardashian is proud her Good American brand gets "down and dirty" with their products.

The 34-year-old 'Keeping up with the Kardashians' star co-founded the denim label in alongside Emma Grede and is pleased they get real people in all shapes and sizes involved in testing the garments for practicality and performance, rather than relying on machines and technology.

She said: "It blows my mind to think that the average woman in America is a size 16 [UK size 18] and that no one is catering to her. There are billion-dollar brands that still don't perfect their performancewear.

"They test on machines instead of people. Whereas Emma gets women into the design studio to do squats or bend over, and then asks the other women to see if they are revealing anything - we can get down and dirty over there."

The cult brand - which is available from a size 0 to 24 - has more than 12,000 women sign up each time Khloe posts about casting sessions on Instagram.

And 35-year-old Emma - who is married to Jens Grede, the co-founder of Frame Denim - explained the importance of giving women a choice and pushing the boundaries of the norms of the fashion industry.

In a joint interview with Sunday Times style magazine, she said "I think women can sense the authenticity of what we are doing - they can smell bulls**t. We want to showcase real women with real lives and highlight their differences. Hopefully Good American has a lot to do with a shift in the fashion industry. 

"People know that we have been successful in a short amount of time. We've given women a choice, rather than offering a few popular styles in a couple of extended sizes, because that really isn't the point is it? So often fashion, it's a little more than a feeble attempt to tick a box."