Kendall Jenner tricked Kim Kardashian West into thinking she was pregnant.

Kendall Jenner

Kendall Jenner

The 20-year-old model teamed up with her half-sister Khloe Kardashian to make a prank call to their older sibling - who has kids North, two, and Saint, six weeks, with husband Kanye West - and break the news she was expecting her first child.

Kendall said: "I was calling you because I wanted to tell you something and I haven't told anyone yet because I feel like you could help me figure out what I should do. I am pregnant."

Watch the video - the reaction will surprise you

However, Kim didn't seem too concerned and used Kendall's bombshell to talk about her own problems.

She said: "I don't know. I'm not the one to talk to. I've had the worst experience and I'm so fresh off of the worst birthing experience.

"I mean, today is not the day because I'd literally be a little more negative because I'm on like one hour of sleep because North was up all night and I was feeding her every two seconds and literally my day has been so crazy and I had no sleep and I want to die but oh my god it's so hard."

Even when Kendall - who was a guest on Khloe's new show 'Kocktails With Khloe' - pretended to cry, Kim still didn't seem focused on much more than her own problems.

She said: "Do you want me to come over? I can bring, like, my 30 kids and you can babysit for two seconds and see how you feel."

Khloe then ended the call and invited Kim on her show - when she loses her baby weight.

Khloe said: "I love you and when you lose a few pounds I want you to come on 'Kocktails With Khloé'!"