It's a sad day for Lamar Odom and Khloe Kardashian, to say the least.

Lamar's close friend, Jamie Sangouthai -- who viewers will remember from his frequent appearances on their E! reality show "Khloe & Lamar" -- has passed away. He was 37 years old.

Jamie reportedly died from a drug overdose, according to Us Weekly.

"When does it stop? RIP Jamie Sangouthai," Khloe tweeted on Sunday.

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"Life doesn't get easier but I promise you that life will make you stronger," she also Instagrammed alongside a picture of a black-and-white cartoon photo of a woman crying.

Khloe's best friend, Malika Haqq, also took to Instagram to mourn Jamie's death, posting a throwback photo of the two of them alongside the former couple. "Thru good and bad times life shows us every spirit matters and leaves a print on the hearts of others after they have passed... RIP Jamie Sangouthai #GodHelpUsAll," she wrote.

A photo posted by Malika (@forevermalika) on

Jamie was close friends with Lamar, 35, since high school. He served as one of the NBA star’s best men during his 2009 wedding to Khloe.

"Lamar is beside himself. This is the worst tragedy," a source tells Us. "They were best friends, like brothers."

"Lamar is going to take this really hard," another source adds.