Khloe Kardashian says Kourtney Kardashian is "the yin to my yang".

Khloe Kardashian and Kourtney Kardashian

Khloe Kardashian and Kourtney Kardashian

In an emotional tribute to her older sister, 30-year-old Khloe has heaped praise on her sibling, who celebrates her 36th birthday today (18.04.15), expressing her "love" and "respect" for her.

Khloe posted on Instagram: "Happy birthday to one of the most monotone chicks I've ever met. It's one of my favorite things about you!! Bible! Every single day I become more and more thankful for how many permanent God given best friends I have in my life.

"Kourt you are the yin to my yang, the Siegfried to my Roy, the Lucy to my Ricky, The Thelma to my Louise, the Wayne to my Garth, the Posh to my David, the sugar to my spice, the icing to my cake.

"I cannot express how much I love you, respect you, admire you... You inspire me every day. I couldn't ask for a better big (little) sister. My life would be meaningless without ALL of you. So with every single birthday I am more and more appreciative that we get to spend another year together only strengthening our bond as soulmates every single one of us. (sic)"