WATCH: Kim Kardashian Left Blac Chyna Hanging on Speakerphone While Rob Brushed His Teeth

This is a sibling cardinal sin.

Kim Kardashian is feeling a little awkward about the interconnected love lives of her brother and sister. In a clip for the upcoming episode of Keeping Up with the Kardashians, Kim describes a recent call with her brother Rob to Khloé and Kourtney that ended with the dial tone when she hung up on his fiancée Blac Chyna because she had no actual words to say.

“So I called Rob and he said that Chyna wants to talk to me and you know I just told him that I’ll talk to her when I’m ready,” says Kim. “And so he put me on speaker and then he was like, ‘Oh Kim, Chyna’s in the room, I just wanted to tell you so you didn’t think I was alone.'”

Chyna attempted to say “hi”, but Kim didn’t reciprocate because she “froze”.

“And so I go, ‘OK gotta go bye.’ And I hung up,” she continues.

Kim continues to explain how Kylie Jenner’s relationship (RIP) with Chyna’s ex- Tyga made her feel “uncomfortable” initially because Chyna was a former friend of hers.

“I had no choice but to take my sister’s side,” says Kim. “That’s my sister … I’ll talk to [Chyna] when I am ready.”

Watch the full clip in the video embedded below.