The 27-year-old model and the 33-year-old Danish DJ and producer have been "dating for a few weeks", reported Ace Showbiz.
Karrueche and Morten went public with their relationship on December 11 as they stepped out together for KURIOS' "Cabinet of Curiosities Cirque du Soleil" show in Los Angeles.
The couple later went to The Nice Guy in West Hollywood, where Justin Bieber delivered an impromptu performance on the piano.
Morten Breum is a DJ originally from Aarhud, Denmark. He is currently living in Los Angeles where Karrueche is also residing.