The reality star has been more open about expecting baby no. 2 than when she was pregnant with daughter Stormi. Last month, a source told ET that Kylie "loves being pregnant and enjoyed her last pregnancy out of the public eye."
"She wanted to be able to have some of that same experience this time -- but it was not the best kept secret!" the source added.
A source tells ET, "Kylie is most excited about giving Stormi a sibling, and Stormi is over the moon ecstatic."
"Travis and Kylie are trying to include Stormi bit by bit and doing things like involving her in what the nursery will look like," the source added. "They are making sure she knows how loved she is and preparing her to be a big sister by keeping her very engaged."