Kim Kardashian has admitted to ''harassing'' her sister Kourtney with baby questions.

The 'Keeping Up with the Kardashians' star and her partner Kanye West will welcome their first child into the world in July and the brunette beauty has been turning to her older sibling - who has children Mason, three, and Penelope, nine months, with partner Scott Disick - and ''mentor'' for advice as she prepares to become a mother.

In a blog post to mark Kourtney's 34th birthday yesterday (18.04.13), Kim wrote: ''Happy Birthday Kourt! You have always mentored me even if you never knew it. You're my big sis and I look up to you so much! I probably harass you now with all of the baby questions I ask you but it's because you are so good at it. You are such an amazing mom, sister & best friend! I idolize YOU! (sic)''

Kourtney was also honoured by her other sister, Khloe Kardashian, who described her as her ''twin soul''.

Khloe wrote on her website: ''Happy Birthday to my twin soul!! You will always be my hot tamale, my marshmallow mama, my chocolate strudel doodle doo, my pecan pie with whip cream on top! I love you beyond anything you can even understand! May all of your dreams continue to become reality! I adore you minnie mouse!(sic)''