Kelly, 28, issued the warning to her friend Miley after she took to the stage in a skin-coloured rubber bralet and knickers and gyrated against Robin Thicke on Sunday night (26 August).
During their 'Blurred Lines' duet, the former Hannah Montana star repeatedly stuck her tongue out and wiggled it around in an apparent attempt to look sexy, but Kelly has told her to stop!
Speaking on US TV show Fashion Police yesterday, Kelly said: "Miley's my friend and I love her, and I have her back no matter what, but as her friend I'm going to tell her: 'Put your f***ing tongue in your mouth. I love you, but just put your tongue in your mouth!'"
Miley, 21, has certainly caused a stir with Sunday night's performance and it is still being talked about the world over.
But sticking up for her, Kelly told her co-host Joan Rivers: "I look at the performance and yes, I do have a lot of the same opinions as you guys about it. But we're not talking about her performance, we're talking about what she's wearing.
"This outfit Lady Gaga wore to the Grammy's three years ago when she came out of an egg. It's not that original but I do appreciate its reminiscent of the 'Blurred Lines' music video."
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