They were the Beverly Hills it-girls back in the mid '00s. And funnily enough, Hilton was the much more famous one.
This week, Hilton and Kardashian uploaded a selfie together reminiscing about the days when they were the friends on everyone's lips. But it wasn't always smooth sailing for these two.
Here's a complete history of Paris Hilton and Kim Kardashian's tumultuous friendship.
Watch the trailer for Paris Hilton's documentary This Is Paris. Post continues below.
Paris Hilton and Kim Kardashian both grew up in Beverly Hills.
They went to different high schools and had different friendship groups, but they had one mutual friend in common: Nicole Richie.
In 2003, Kardashian appeared on Hilton and Nicole Richie's reality TV show The Simple Life. One of the most iconic moments of the show to this day, was when Kardashian cleaned and organised Hilton's closet for her.
But while people believe that was because Kardashian was Hilton's assistant, that's only a rumour.
"I was not her assistant, but I had an eBay closet organising company and she was one of my clients," Kardashian later told Recode.