"All I'm saying is, I reached out personally. I didn't do a public thing. I didn't want to," she told the magazine.
Gomez and Lovato co-starred on Barney & Friends as children. Gomez later played Alex Russo on the Disney Channel series Wizards of Waverly Place, while Lovato portrayed Mitchie Torres in the network's Camp Rock movies.
"I... I love her. I've known her since I was seven. So... it's... that's what I'll say," Gomez added.
Lovato was rushed to a hospital July 24 after reportedly having a drug overdose at her home. She updated fans in an Instagram post in August, saying her struggle with addiction is something she has yet to overcome.
"The love you have all shown me will never be forgotten and I look forward to the day where I can say I came out on the other side. I will keep fighting," the star said.
Lovato's mom, Dianna De La Garza, had discussed Lovato and Gomez's friendship in an interview with People in March.
"Demi and Selena love each other and always will love each other," De La Garza said.
"They started out together!" she added. "They will always love each other. There's nothing that will ever come between them."