Khloe Kardashian
Khloe Kardashian appeared to have a strained relattionship with Jamie Sangouthai in the Khloe & Lamar reality seriesREUTERS/Danny Moloshok

Keeping Up With The Kardashians star Khloe Kardashian was reportedly "too upset" over the death of Jamie Sangouthai, her husband Lamar Odom's best friend, that she was unable to celebrate North West's second birthday at Disneyland in California.

A source told E! News: "Khloé was too upset over Jamie dying. She wasn't there," in reference to the party.

Kim Kardashian and Kanye West's daughter North was surrounded by many of her loved ones, including aunts Kourtney Kardashian, Kendall and Kylie Jenner, and cousins Mason and Penelope Disick.

TMZ reported that Sangouthai died of a suspected heroin overdose at a Los Angeles hospital on 14 June at the age of 37.

Khloe, 30, reacted to the news via Twitter, posting a series of heartbroken emojis and the message:

She added in a separate post: "Life doesn't get easier but I promise you that life will make you stronger."

The boutique owner, who is believed to have been in Hawaii when the news broke, was seen visiting the family's DASH store in LA with her sister Kourtney the day after North's birthday party.

Sangouthai appeared in several episodes of Khloe & Lamar, the E! star's reality show with estranged husband Odom, although his relationship with the Kardashian sister was portrayed to be strained.

NBA star Odom has not commented on Sangouthai's passing publicly, but a source told Us Weekly that the ex-LA Lakers player is understandably struggling to come to terms with his loss.

The insider said: "Lamar is beside himself. This is the worst tragedy. This is so sad. They were best friends, like brothers. Lamar is going to take this really hard."

???

A photo posted by ✨Jamie Sangouthai✨ (@bigjriz) on