Both clubs, along with Liverpool, were being heavily linked with the Dutchman when he was at FC Twente with his representative, Louis Laros, stating that Gladbach were much keener on his services than the two Premier League outfits.
"There were a lot of clubs interested in Luuk," Laros told Sky Sports. "Liverpool showed interest and also Newcastle were very interested in signing him.
"But everything happens so quickly in football and in the end Gladbach showed the stronger desire to sign him whilst Newcastle were not able to come to an agreement with Twente.
"Gladbach were able to assure him that they trusted him and wanted to give him a prominent role from day one.
"The Bundesliga is very popular in The Netherlands and Gladbach is one of the biggest clubs in Germany."