Los Angeles, June 17 (IANS): Reality TV star Khloe Kardashian was "too upset" to attend her niece North West's birthday at Disneyland after losing her friend Jamie Sangouthai.

According to a source, the 30-year-old was mentally absent from her niece's second birthday party in Disneyland on Monday and skipped the bash after learning about the devastating loss of her estranged husband Lamar Odom's best friend, Sangouthai, reports eonline.com.

“Khloe was too upset over Jamie dying. She wasn't there,” said the source.

Instead, Kris, Kylie and Kendall Jenner, Kourtney Kardashian and her son Mason, five, and Kylie's boyfriend Tyga were on hand to celebrate with North and her parents Kim Kardashian West and Kanye West.

Khloe was one of the first people to reveal the tragic news that Jamie Sangouthai, who was one of the best men at her and Odom's wedding in 2009, had passed away from an alleged heroin overdose.

“When does it stop? RIP Jamie Sangouthai,” she posted on Twitter.

Odom is believed to be "beside himself" by the loss.

"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," said the source.