"I said, 'Hey, my name is Kacey and I am a really big fan. I don't want to offend you or anything, but is there any way you might want to burn one with me?'" Musgraves recalled saying after one of his shows in Nashville, Tennessee.
Musgraves, who would later go on to win two Grammy Awards for her 2013 major label debut album, was hoping to fulfill a fantasy of smoking a joint with Prine. It was also the premise of an unreleased song she had written that somehow ended up on Prine's desk.
Prine, who has survived a couple of bouts of cancer, politely declined.
"He says, 'Well, I don't do that anymore, but if I did, I would with you,'" Musgraves, who is now 28, recalled.
This 70-year-old former mailman from Chicago is the hippest writer in Nashville and still in demand. Prine has become an affable songwriting guru for many of Nashville's talented young artists, including country rebel Sturgill Simpson, Americana darlings Jason Isbell and his wife, Amanda Shires, and rocker Dan Auerbach of the Black Keys.
All those artists have lined up to open for Prine, when they are easily selling out their own venues as headliners.
"I have met some really great people in the last five years that it's easy to see that music in general is in good hands," Prine said in an interview from his office, which is decorated year round with Christmas lights and a white Christmas tree.
Prine published his first book in April, a songbook called "Beyond Words," which features guitar chords, family photos, handwritten or typed lyrics with his editing marks and witty musings alongside some of his most well-known songs, from "Sam Stone," ''Angel from Montgomery," ''Paradise," and "Hello in There." Prine's reinvigorated career came after neck cancer in the late '90s left him with a much lower and grittier voice. After his recovery, he just moved his songs to lower key.
"Some of my oldest songs that I used to perform every night became brand spanking new just because I changed the key," Prine said.
He started his own record label Oh Boy in Nashville in the early '80s, which sold his CDs by direct mail to fans. He enjoys his independence from major labels, even if it has meant fewer sales. He says his only advice to young songwriters is don't give up their publishing rights in a record deal.
"I am not a big one for advice," Prine said. "I will tell them stories about things I have failed at or places I have stumbled and hope they take it as a parable. And maybe apply it to themselves and maybe not."
Auerbach and Prine wrote several songs together, including the title track for Auerbach's new solo album, "Waiting On a Song."
"It was like having a conversation really," the 38-year-old singer said of writing with Prine. "And I think for me, that's what John does so well with his music. It's not over your head. He uses simple language to convey big meaning."
The Grammy-winner has taken on heavy topics including coal mining on Appalachia, the treatment of Vietnam veterans and the loneliness of growing old, and earned praises from Bob Dylan, Bonnie Raitt and Kris Kristofferson, who helped Prine get his first record deal. But he also likes to write with humor, as evidenced by another popular duet with Iris Dement "In Spite of Ourselves," that contains some of his best one-liners about love and marriage.
"I think John is very youthful at heart," Musgraves said. "He's a big kid. So naturally he gets along with people that are younger than him. But also he probably recognizes himself in a lot of the up-and-coming songwriters that respect him."
Even a trip to the grocery store is an opportunity for aspiring writers to pitch him. "I used to leave Kroger with cassettes in my pockets because people would drop CDs and cassettes because they want John Prine to hear it," Prine said.
His last album in 2016 was a collection of classic country duets with artists like Musgraves, Alison Krauss and Miranda Lambert. He hasn't released an album of new songs in 12 years, but his wife and manager, Fiona, and his son, Jody, who runs his label, convinced him it was time again.
He's going back in the studio in July to record new music and he's also been nominated for artist of the year at this year's Americana Honors and Awards show held in September.
"I like the scene in Nashville," Prine said. "I am not particularly happy with modern country music, but it's part of a tradition. It will come and it will go, but it will always revert back to what country was before. I can see it coming around again. I am going to stick around Nashville and see what happens."
Follow Kristin M. Hall at Twitter.com/kmhall