"She's not taking it too seriously, just having fun," people.com quoted a source as saying.
Khloe filed for divorce from husband and basketball player Lamar Odom in December and has been seen with Montana a number of times.
The duo was seen in a music listening party together at rapper Hooray Henry's place in West Hollywood April 9.
"Khloe is totally with him. She's having so much fun with him. She wasn't sure at first where things would lead but he treats her amazingly. That makes her feel really good. She deserves tha," said another source.
Next evening the pair was seen at Cecconi restaurant, Los Angeles for a dinner with sister Kourtney Kardashian and her longtime beau and TV personality Scott Disick.