Khloe Kardashian is reportedly angry at Lamar Odom for being kept in the dark about his whereabouts.

The basketball star is thought to have checked into rehab, but his wife is said to be ''p***ed off'' at not being trusted with her husband's location after recent rumours the couple's marriage is on the rocks due to his alleged drug habit.

An insider told ''[She is] relieved that Lamar has finally gone to rehab, if that's where he really is, but she is p***ed off she doesn't even know his location.

''She has stood by him for the past two years as he descended into a nasty addiction of Oxycontin and cocaine.''

It is said that Lamar not telling Khloe where he is is a ''knife in her back'', and despite asking those close to him, she hasn't been able to get any information.

The source said: ''For him to cut Khloe out is just a knife in her back. Khloe has reached out to Lamar's sports agent Jeff Schwartz, but has got no information about Lamar's whereabouts.''

The news comes after Lamar was arrested on August 30 for Driving Under the Influence [DUI] and had his licence suspended after refusing a chemical test.