The 26-year-old spent a stint on loan at Dortmund in the 2008-09 season, under the guidance of Klopp, and impressed before continuing his career at Portsmouth and the Rossoneri.
The Ghana international caused a stir when he signed for Dortmund's arch-rivals Schalke last week, and Klopp made comments in jest about the 26-year-old after admitting his surprise at the midfielder's choice of destination.
"Many people thought it was funny, but I didn't," Boateng told Sport-Bild.
"Even if 'Kloppo' and I have a good relationship, he's not going to hear me say a bad word about him, but this press conference surprised me."
Boateng played a key role in Schalke's 2-0 Bundesliga win over Bayer Leverkusen on Saturday, ending a three-game winless run in the Bundesliga in the process.
The Ghanaian joined Schalke from Milan for €15 million last month, signing a four-year deal with the German club.