Kim Kardashian and Demi Lovato
10/01/2011 at 12:00 PM EDT
and Kim Kardashian
have developed a close friendship
– and their bond was solidified by Kardashian's loyalty during a tough time for her pal.
When Lovato, 19, worked through her eating disorder and other issues last year and entered treatment
in October, Kardashian, 30, was there for her.
"I feel like there are some people that you're friends with that talk to you on Twitter or text," the Disney star tells Billboard.com
. "But the people that are really there for me are the people that were there for me when I went into treatment.
"The people that were calling me while I was in there were Kim Kardashian and Selena Gomez
," adds Lovato. "Those two girls, they meant the world to me. They still do."