Toby Keith shared the story behind one of his latest songs, “Don’t Let The Old Man In,” and revealed the legendary actor who inspired its title: Clint Eastwood.

Keith, 62, remembered a conversation with Eastwood, 93, that gave him the idea to write “Don’t Let The Old Man In.” The country music icon said it happened during the time Eastwood was filming The Mule, a 2018 thriller that follows, “a ninety-year-old horticulturist and Korean War veteran (who) turns drug mule for a Mexican cartel,” reads its description on IMDb. Keith’s song ultimately ended up in the film.

“It’s an interesting story, how this song came to be,” Keith said in a video shared on Instagram on Friday (December 1). “Clint Eastwood, when asked by me, what he was gonna do on his birthday, he said he was gonna go shoot a movie. He was 88 years old, and I said, ‘what do you do to keep yourself going?’ He said, ‘I try to get up and be productive, and don’t let the old man in.’ So, I wrote (the song, and) sent it to him. He put it in that movie, The Mule, and then it exploded on NBC when I sang it on the People’s Choice [Country] Awards when I was getting the Icon (Award).”

Keith referred to the inaugural People’s Choice Country Awards, which took place in late September in Nashville, Tennessee. Keith was awarded the Country Music Icon Award that evening, and took the legendary Grand Ole Opry stage with a heartfelt acceptance speech. The Country Music Icon later announced a few upcoming shows in Las Vegas, his first shows back amid his ongoing cancer battle.

Keith’s story about “Don’y Let The Old Man In” comes shortly after he released 100% Songwriter, a collection of songs he wrote on his own. The album includes “Should’ve Been A Cowboy,” “Country Comes To Town,” “Courtesy of the Red, White And Blue,” and other career-spanning hits. Find the full album on iHeartRadio here.