It seems to apply to all musical instruments including the voice. Part of the trick is to stop identifying oneself with the thinking process and the talking inside one's head. Those are tools in our toolbox which can and should be laid aside at times that they are more of a hinderance than a help. They can be picked up and employed again when and where it's appropriate.
OMG that's so true. When I can get my mind out of the way I play so much better - as soon as I start engaging with cognitive thoughts while playing I know I'm lost