It was the biggest mystery in the entertainment world and now it's finally being addressed in upcoming episodes of Keeping Up with the Kardashians - Kylie's pregnancy.
A sneak peek at Sunday's episode, Kim and Khloé sit down to chat about Kylie.
"The funnest game ever is the Kylie pregnancy game, just to see what people think. Like, there were pictures of her out on TMZ and she looked so skinny."
Khloe added "I know, 'cause it's the angle. They got her from face-on. But if they got a side shot, it would have been over for her."
Later, Kim tells Kylie that her pregnancy was the "best-kept secret of our generation."
"Your friends deserve awards. Now you know you have some real ones. That wouldn’t have happened in my day."