Sources with direct knowledge tell TMZ ... the trio is planning to fly to Toronto later this week to be in attendance for Andrea's funeral. We're told Tristan paid for and planned the whole service, which will be an intimate and beautiful celebration of her life.
Much like Khloe did last week, when Andrea died unexpectedly, we're told Kim, Kris and Khloe want to be there to comfort and support Tristan. Sources tell us it's important to the Kardashian clan to be there for loved ones, especially during tough times like this.
TMZ broke the story, Andrea suffered a heart attack at home last week -- she was rushed to a local hospital where doctors tried to resuscitate her, but she didn't make it.
Khloe initially flew to Toronto to be with Tristan, and Kim ended up going too … but the sisters came back to L.A. Monday. Sources say Khloe was close to Andrea, and losing her has been sad and shocking to everyone.