Kylie Jenner was suspected of having a brain tumour as a child.
Kim Kardashian West with Kylie and Kendall Jenner
The 17-year-old reality star spent around a month in hospital when she was younger, and her older half-sister Kim Kardashian West - who is pregnant with her and husband Kanye West's second child - credits the family's experiences with why she is so keen to help sick children and makes regular hospital visits.
Kim said: "I was a teenager and I would have to watch Kylie while my mom was in the shower, for example. That's why I got involved.
"I'm choosing to get involved in children's hospitals. You don't have to have money to give back and that is so much more meaningful - you can give your time."
The 'Keeping Up With the Kardashians' star - who already has two-year-old daughter North with Kanye - also revealed she will be flying to New Orleans in August to join a fan for a birthday dinner after they met at a concert.
Speaking to the prestigious San Francisco Commonwealth Club in San Francisco, she said: "I tweeted and asked what her what seat she was in so I asked her to come and sit with me.
"I love her energy, I love following I'm so excited to spend her birthday with her. That would never happen unless social media existed."
But the 34-year-old beauty admitted she often "over-shares" on social media.
She added: "I'm so open, I definitely over share but I'm really engaged. I do it all myself. I can tell when someone in the business isn't doing it themselves."
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