Pietersen has been criticised by South African players and fans ever since his cricketing defection to England in 2004.
That abuse has continued right through to the current Test series, with Proteas captain Graeme Smith stating that he is still target No.1 for his side.
But so far eight one-dayers against his country of birth (South Africa) has seen Pietersen hit three centuries. And having produced the goods in those high-pressure games, Cook believes it can only be easier in the Test arena.
"None of the players take too much notice of what is said before a Test series. I know I don't. All the talking stops when we walk out at Lord's. A great series starts in which we hope to come out victorious," The Sun quoted cook, as saying.
"I imagine it's very strange for Pietersen playing against his country of birth. He has a great record against them in one-dayers and I"ve got no doubts he will continue that in the Tests," he said.
"KP played against South Africa before in front of a hostile home crowd - and his reply was a bucketful of runs," Cook added.
The first Test between England and South Africa starts on Thursday at Lord's.