Reality TV star Kim Kardashian West is not happy that her younger sister, Khloe Kardashian, is still flirting with her ex-husband, Lamar Odom. Kim has strong opinions about the subject and isn’t afraid to let her sister know how she feels about the constant contact between the exes.

“As a big sister, I’m protective. For her to just be flirting with him on the phone makes me sick to my stomach,” says Kim. She opens up about the subject in a clip shared by People from an upcoming episode of “Keeping Up With the Kardashians.”

In the video embedded below, Khloe is on the phone with Lamar, while Kim stares at her sister from across the room. Khloe feels the heat from Kim’s glare but she tries to lighten the situation by saying that Lamar says “hi” to Kim, her husband Kanye West and their daughter North.

Kim clearly isn’t charmed and continues to stare down her sister. When Khloe hangs up, Kim gives her sister a piece of her mind and says that she can’t take it that Khloe is still flirting with Lamar.

“I don’t know why Khloe and Lamar are talking, but he hurt her so badly,” Kim tells the camera. Khloe and Lamar were married in 2009, and were together for 4 years. In December 2013, Khloe filed for divorce after cheating and drug abuse allegations against Lamar surfaced.

She later spoke openly about his cheating in episodes of “Keeping Up With the Kardashians.” However, despite the tumultuous end to their relationship, Khloe has tried to keep in touch with her ex. In another earlier episode of the family’s reality show, Kim and Khloe got in another argument after Khloe mentioned that she wanted to check up on Lamar while they were in Armenia.

The divorce papers were finalized earlier this year but the drama between Khloe and Lamar has continued. Back in August, Lamar allegedly ambushed Khloe outside her gym. He has since claimed that it was a planned meeting but Khloe has not commented on the incident.