It's called The Story of Lex and Livia. I'm assuming the series is called Rebels: City of Indra, but when I checked on Goodreads it was just City of Indra.... so IDK. It releases June 3rd 2014. You can preorder it on Barnes and Noble, Amazon, and the publishing company [I think...] Simon & Schuster.
It may just be me and my biased opinion but I have low expectation for this. I'm not hating but I am kind of doubting. I may be wrong only because I haven't read to many books by people like Kendall and Kylie. I read Lauren Conrad's LA Candy trilogy and I really enjoyed it. It gave me sense of fame and it was very straightforward. I could see why some people wouldn't like but thats their opinion. It's something that isn't very difficult to write. But the thing about dystopians is you have to set up the world and describe the setting enough so that the reader doesn't get confused and then you have the character set up which is something you have over time of the book. It's not very good to throw the character at the reader at the beginning of the book.
So, tell me, are you going to read it?