Kim Kardashian: Kylie Jenner's pregnancy was the 'best kept secret'

Kim Kardashian West thinks Kylie Jenner's pregnancy was "the best kept secret" of this generation.

The 21-year-old reality star managed to keep her pregnancy under wraps up until the moment her daughter Stormi was born on February 1 this year, and her older half-sister Kim has said she can't believe how well her sibling managed to avoid having the news leak.

Speaking on a promotional clip for the upcoming episode of 'Keeping Up with the Kardashians' - which was filmed whilst Kylie was still pregnant - the 37-year-old star said: "The funnest game ever is the Kylie pregnancy game. Just to see what people think. There were pictures of her out on TMZ and she looked so skinny."

The beauty - who has North, four, Saint, two, and Chicago, almost eight months, with her husband Kanye West - then added to Kylie in her confessional: "Your pregnancy has been the best kept secret of our generation.

"Your friends deserve awards. Because seriously, now you know you have some real ones because that never would've happened in my day."

But the 'Life of Kylie' star insisted she wasn't trying to keep her pregnancy a secret for the sake of a big reveal, but instead just wanted privacy.

She said: "Like, I'm not trying to keep a secret, I'm doing this for myself."

The comments come after Kylie's sister Kendall, 22, recently praised her for being able to stay out of the spotlight.

She told her sibling: "One of my favourite things you did during your pregnancy ... was that you stayed really low-key during your pregnancy. I think that it was kind of beautiful ... What were you thinking when you did that and what was your whole process behind that?"

To which Kylie responded: "I knew that it would be better for us, if me and Stormi just stayed kind of low-key. Your hormones are going crazy and your emotions are more heightened, and I just felt like I wasn't prepared to ... I just knew that it would be better for me, and I could enjoy the whole experience if I did it privately. I just felt like it was a sacred special moment and I wasn't ready to share it with everybody. I just wanted to keep that to myself."