The singer wrote a piece on the rapper as part of TIME magazine's 2019 TIME 100 Next, in which he admits that, upon first hearing the song, he said he had nothing to contribute to make it better and took some convincing to get involved.
"I was having coffee and Ron Perry from Columbia Records sent me 'Old Town Road.' He said Lil Nas X wanted me to sing on it. But I told Columbia it was perfect. I couldn't do anything to it," he writes. "They asked if I'd give it a shot and come into the studio with Nas to record a third verse."
Cyrus went on to explain just how straightforward the writing process was, as well as sharing the indelible impact Lil Nas X left on him.
"We wrote it with R&B songwriter Jozzy, and it was born right there in the studio. It was magical. I told Nas he was going to be a light in this world and he would shine brighter than anyone else. And he has," he shares. "He's brought everyone together, from all musical genres and generations. 'Old Town Road' changed my world -- and his -- forever."
On Wednesday, it was announced that the pair won the Musical Event of the Year CMA Award ahead of the awards show that evening. Nas soon tweeted about the exciting news, which was announced on Good Morning America, writing, "LET'S GOOOOOOOOO!!!!!!"
This is just the latest honor the track has received after setting a new record, spending a whopping 19 weeks at the top of the Billboard Hot 100 chart earlier this year.
ET caught up with Cyrus at MTV's Video Music Awards back in August -- where "Old Town Road" won Song of the Year -- and he raved about the fan response to the massive hit.
"Tonight's just a celebration, to be here with these fans, the fans made the song happen," he said. "It's their record and being here tonight is just so much fun."
"It's crazy, it's crazy. Again, the people took this song and they made it their own, you know," he stated after introducing Nas' performance of "Panini." "It's just been a heck of a ride and it's been a lot of fun," he gushed. "Seeing Lil Nas take the stage just now, I mean, he's electric."
See more on Cyrus and Nas below.