According to UsWeekly, the 33-year-old rocker and the Danish model, 21, have been dating for several months. She has even been spotted on the set of "The Voice," in which Levine is a mentor.
The couple plan to go public with their romance. An insider explained: "Nina is happy she can be open and not hide anymore."
Levine was linked to Victoria's Secret beauty Behati Prinsloo last year. A source told the magazine: "Behati was in and out, but they finally ended it. It wasn't an abrupt ending."
Prior to that, Levine dated model Anne Vyalitsyna, also a Victoria's Secret and Sports Illustrated model.
Levine recently talked about his distaste for drugs after a bad experience with prescription medication Ambien.