The Keeping Up With The Kardashians star was appearing on US TV show Entertainment Tonight when she was asked to clarify the speculation surrounding Bruce.
It's been claimed by some that Bruce is transitioning to become a woman, and a US magazine even printed a picture of Bruce on its cover recently, Photoshopping in make-up.
But Kim, 34, refused to be drawn on the speculation and said it was up to Bruce to say what he wanted to say when the time was right for him.
"We support Bruce no matter what, 100 per cent. On this on,e I will say I think Bruce should tell his story his way," said Kim.
"I think everyone goes through things in life, and I think that story and what Bruce is going through, I think he'll share whenever the time is right. I feel like that's his journey to talk about."
All Kim would say is that Bruce is the "happiest" she 's ever known him to be.
Bruce himself has never addressed the rumours.
The Olympic champion divorced Kim's mum Kris Jenner last year, after they stunned fans by announcing in October 2013 that their 22-year marriage had come to an end.
He and Kris have two children together: Kendall, 19, and Kylie, 17.
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