Williamson is revelling in the opportunity to work with a man who has plied his trade at the highest level for much of the 18 years since he came through the ranks at Tottenham.
Asked if Campbell's arrival had come as a blow, Williamson said: "No, not one bit, I looked on it as a massive opportunity.
"He is a player I have always admired and looked at from afar through his career, and I just thought what an amazing opportunity it was to learn from such a character day in, day out.
"I just thought it was a great opportunity because I am still learning my trade and trying to ply it at the top level, and it's a good thing for me.
"Coming to a club like Newcastle, you are never going to be handed the shirt - there is always going to be competition, and I know that.
"That's healthy, that's part of why you want to test yourself against the best players."