Since the end of the season, Klopp has paid tribute to the departing Wijnaldum on a number of occasions, with the midfielder also returning the favour to his former boss.
And now, on the German's birthday, the ex-Liverpool midfielder has taken to Twitter to share a heartfelt message in honour of his old mentor.
"You've been an inspiration to me these last five years and a fantastic boss," he wrote.
"Thanks for always believing in me and supporting me in the amazing way you did!
"Wishing you a happy birthday and all the best #JürgenKlopp "