Clint Eastwood inspiration behind Toby Keith's 'Don't let the old man in' track

Eastwood loved the song and asked if he could include it in his movie.

Veteran actor Clint Eastwood was the inspiration behind singer-songwriter Toby Keith's track "Don't let the old man in".

Keith said he was inspired by a conversation with the 88-year-old actor-director about his latest movie "The Mule" and his work ethic.

''He said, 'I just get up every morning and go out. And I don't let the old man in'. And I thought, I'm writing that.

''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. 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," the singer told Billboard magazine.

Eastwood loved the song and asked if he could include it in his movie.

''He said, 'I've got a spot in the movie and I'm putting it in there.' And then Warner Bros. called asking did I read the script before I wrote this song because it fits perfectly. He wanted it sick and tired and dark like that," Keith said.