It's an emotional time for the Kardashian-Jenner family. In a new sneak peek clip from the Keeping Up With the Kardashians special, About Bruce, Kim Kardashian confides in Kendall and Kylie Jenner about their mom Kris Jenner's reaction to the news that her ex-husband Bruce Jenner is transitioning from a male to a female. 

"He's going to tell his full story," Kardashian, 34, tells her half-sisters about Bruce's historic Diane Sawyer interview. "At first I was like, 'I'm totally going to cry, I'm totally going to cry.' My throat was literally burning, just talking to him." 

But in addition to being scared for her stepfather, the mother of North West was also concerned about the impact it would have on Kris. 

"I was thinking [about] Mom," she continues. "This is really hard for her. It's just so sad. She cries all the time. It makes me really sad, but we should really appreciate all the things she does for us because she does a lot."

Watch the emotional clip now. To see part one of About Bruce, tune into E! at 9 p.m. ET on Sunday, May 17. 

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