Next month will mark three years since Kenny Rogers passed away, and his loss is still felt deeply by many, including his good friend, Dolly Parton. Rogers was 81 years old when he died at his home in Georgia, a loss Parton still deeply mourns.

“I miss him so much,” Parton tells People. “I’ve lost so many wonderful people in my life in the last few years. But Kenny — he was very, very dear and special and I never get tired of hearing us sing, all the years that we were on stage together.”

Parton and Rogers were not only good friends, but frequent duet partners. The two singers released several albums and songs together, including their 1983 No. 1 hit, “Islands in the Stream.” The song became their most popular collaboration, with fans still requesting the song more than 30 years after it was released — not that Parton minded.

“You know how sometimes you get tired of singing something because it just becomes routine?” Parton reflects. “But I would always lighten up when that particular song was due in the setlist. It just always made everybody feel so good in the audience and the audience always loved singing it. I never got tired of Kenny’s voice.”

The last song Parton and Rogers released together, “You Can’t Make Old Friends,” was written by Ryan Hanna King, Don Schlitz and Caitlyn Smith. The title track of Rogers’ album, out in 2013, the song perectly sums up the close relationship between the two, which is why Parton has a hard time singing it now.

“[We recorded that song] just in time too, honestly,” Parton says. “And now I can’t hardly sing it. … You can make new friends that feel like old friends, but there’s just something about the people that have spent years together. You have a history, and you learn about each other, inside and out. I knew Kenny very well. We’re very similar. We’re like brother and sister really.”

As the third anniversary of Rogers’ death draws near, the Rock and Roll Hall of Fame member finds solace in believing Rogers is still using his talents, just not in this life.

“He’s up there singing,” Parton maintains. “I know that.”