The fullback joined the Toon on deadline day in a season-long loan from Eintracht Frankfurt - but only after being convinced by former Newcastle midfielder Wijnaldum.
He told AD: "I spoke with Gini.
"He said, 'Believe me, Jetro. Go to Newcastle. A good city, warm people. A great atmosphere. Just do your thing and it'll be fine'.
"I trusted that."
On leaving Eintracht, Willems added: "If I wanted to achieve my goals and further develop myself in a more natural and trusted position, I had to do it somewhere else. I have just turned 25 years old."