Kim Kardashian West has admitted she can be "so mean" to her sister Kourtney Kardashian.

Kim Kardashian West

Kim Kardashian West

The 38-year-old reality star got into a heated argument with her older sister during an episode of 'Keeping Up with the Kardashians' last week, after Kim accused Kourtney of not wanting to document her romantic relationships on the program, and leaving Kim and their younger sister Khloe Kardashian to "pick up the slack".

And in a preview clip for Sunday's (15.12.19) episode, Kim is seen admitting she may have gone too far in her critique of 40-year-old Kourtney.

She says: "I want to fix, you know, my relationship probably with Kourtney. I mean, I can be so mean."

Kim made her comments in a clip which shows family matriarch Kris Jenner telling her children she wants them to "strengthen" their relationships with one another.

Kris said: "I want each one of you to pick one person sitting here and tell them what's the one thing you'd love to focus on strengthening in your relationship. What we're gonna do is build the communication."

And the SKIMS solutionwear founder wasn't the only one who reached out to Kourtney, as 35-year-old Khloe also admitted her bond with her eldest sister can sometimes "fizzle".

The 'Revenge Body' star said: "I feel like Kourtney and I sometimes fizzle. So, I think I would love to get us back on course and maybe not be so reactive. For myself."

In last week's episode, Kim accused Kourtney of not pulling her weight on the family's reality show, and threatened to axe her from the program if she didn't agree to film more material.

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?"

The conversation then sparked a debate on social media about the involvement of the family's youngest stars, Kendall and Kylie Jenner, and Khloe revealed they have different contracts to their sisters.

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?"

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

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