The England captain has found himself largely out of the public eye since victory over Australia was secured, while Pietersen has enjoyed the limelight.
He and new girlfriend Caprice were at the centre of attention at the International Cricket Council's awards dinner this week and, although Vaughan has already seen Pietersen deal with plenty of pressure in his short England career, he now faces increased focus on his private life.
"As long as we can keep him grounded and he doesn't get too carried away with his celebrity status, this young man can become one of the very best," wrote Vaughan in his autobiography 'Calling The Shots', serialised in the Daily Mail.
While Vaughan now exalts his team-mate to such a level, the captain admits he initially had concerns over the South Africa-born batsman's ability at the highest level.
"Initially I wondered if he was just a banger but those doubts were dispelled once I spent a bit of time with him in the middle," Vaughan explained.
He added: "There isn't a lot that hasn't already been said about Kevin Pietersen, even though he has only been in Test cricket two minutes. KP has made that big an impact."