Charles Kelley was there when Toby Keith had the inspiration for what became his current hit single, “Don’t Let The Old Man In.” The song, which was first released in 2018, was recently released again, after Keith’s live performance at the People’s Choice Country Awards, becoming the most-added at radio.

The Lady A singer shared a story on social media about the song, and how close he was the day Keith had the inspiration to write the hit song.

“I’m 90 percent sure I was with you the day that you came up with that song idea. We were playing in The Clint,” Kelley told Keith on his Instagram Story, referring to a golf tournament. “You were playing with Clint Eastwood, and I was playing with his buddy, Steve John … I believe that you asked Clint, ‘What’s the key? What’s the key to just growing old?’ and he had said, ‘Don’t let the old man in.’

“I can’t remember if you wrote it down,” Kelley continued. “You obviously must have held onto it. It’s just crazy to think that it’s now the No. 1, most-added. It looks like it’s about to be a hugely impactful song. It’s pretty cool to be a fly on the wall during that moment. That’s what great songwriters do.”

Keith recalled the day he had the idea to write “Don’t Let The Old Man In,” which was indeed inspired by a conversation he had with Eastwood, who was turning 86 the day his movie, The Mule, was set to start filming. Keith asked him how he keeps going day after day, year after year, and was taken aback by his answer.

“He said, ‘I just get up every morning and go out. And I don’t let the old man in,’” Keith told Billboard. “And I thought, I’m writing that.”

Once Keith had the idea for “Don’t Let The Old Man In,” he could think of nothing else until he finished the song.

“People were talking to me and they would say, ‘Did you hear what I just said?’ And I was like, ‘No,’ because I wasn’t listening to any conversations,” Keith said. “I was consumed by ‘Don’t Let the Old Man In.’ I worked so hard on it. When I finally sang the line, I thought, ‘It’s got to be dark. It’s got to be a ballad and it’s got to be simple.'”

Although he didn’t write “Don’t Let The Old Man In” with hopes of getting it into The Mule, Eastwood was so taken by the song, he used it in the film. The live version also topped Billboard‘s Country Digital Song Sales chart for two weeks when it was released.

Keith just added a third and final night to his run of shows in Las Vegas, at Dolby Live at Park MGM Find all of Keith’s music and touring updates at TobyKeith.com

Read ‘Toby Keith: 11 Things To Know About the Patriotic Singer’ here.