Lamar Odom is reportedly angry that his estranged wife Khloe Kardashian has moved on from their relationship.

The 29-year-old Keeping Up With The Kardashians star filed for divorce from the 34-year-old professional basketball player in December, after four years of marriage, citing irreconcilable differences.

Kardashian is now rumoured to be dating rapper French Montana and the two have been spotted together frequently in the recent weeks.

"Khloe is totally with him. She's having so much fun with him," a source told People. "She wasn't sure at first where things would lead but he treats her amazingly. That makes her feel really good. She deserves that."

According to Us Weekly, Odom is "unimpressed" that she has moved on already.

"He thinks Khloe is just doing this to get to him. He's furious," a source told the publication.

The former NBA star recently accepted that his marriage is over and is expected to formally submit a response to her divorce petition in "the next few weeks".

"Lamar finally gets it, his marriage to Khloe is over," a source told Radar Online.

"There was a time when Lamar said he would never give up on getting back together with Khloe, but he recognizes she has obviously moved on. He will tell his attorney to submit a response to Khloe's divorce petition. It isn't expected to be a long drawn out divorce, since there is an iron-clad prenup in place," the insider said.

Meanwhile, French Montana is still legally bound to estranged wife Deen Kharbouch, with whom he has a four-year-old son, Kruz.