Kendall Jenner's 'heart dropped' the first time she saw dad as Caitlyn

Kendall Jenner's "heart dropped" the first time she saw her father dressed as a woman.

The 21-year-old model is the daughter of Kris Jenner and Olympic champion Caitlyn Jenner, known as Bruce before announcing her decision to live as a female in 2015.

Prior to Caitlyn's interview with Diane Sawyer, in which she revealed her intention to transition into a woman, Kendall and her family had noticed hints about Bruce's alter ego when they found items such as a wig and nail polish around the house.

And a year before her father came out as transgender, Kendall saw Bruce in the kitchen dressed as Caitlyn during a nighttime kitchen run.

"My heart dropped," Kendall told Harper’s Bazaar of her feelings at that moment. "That's when she would dress as herself, at four in the morning, before we would get up. So that was like, 'Whoa,' for a second."

Kendall insists that by the time Caitlyn went public with her transgender identity, the family already "kind of knew". However, adjusting to the loss of her father and the introduction of a new part of the family has taken some getting used to for Kendall and her sisters.

"If I would talk about it, I would cry, just because you're mourning someone... losing someone," she explained. "The person is still there, of course, but physically you're losing someone. It was my dad who I grew up with my whole life and who raised me. It's an adjustment, for sure.

"But honestly, you start to realise that this person is still alive. This person is still here. They are still a blessing. They are still awesome. I realised that I should just be thankful that I still have my dad. It starts to just become normal. You're just like, 'OK, cool.’"

Caitlyn underwent gender reassignment surgery in January (17), detailing her decision to have the procedure in her upcoming memoir The Secrets of My Life.