Kardashian, 35, posted the message for the former Olympian, who was known as Bruce Jenner before undergoing gender transition in May, on Instagram to mark her 66th birthday on Wednesday, October 28, reported Female First.
Alongside of a photograph of them enjoying a pre-birthday lunch, the pregnant 'Keeping Up with the Kardashians' star wrote, "Happy Birthday Caitlyn! Are you 66 or is Caitlyn 1? lol That was the debate at our b'day lunch yesterday! Have the best day ever filled with lots of love & laughs! You have shown me what it's truly like to live an authentic life without caring what the world would think! I love you!"
"What a brave soul! I'm happy you are living your authentic life! You are my Woman Crush Wednesday.