In a new interview with The LA Times, The Heartbreakers opened up about An American Treasure, their upcoming four-disc box set. The box set includes original recordings of some of Tom Petty and the band's biggest hits, as well as demos, outtakes and live performances. It also features 10 previously unreleased tracks.

Keyboardist Benmont Tench talked about "Lonesome Dave," a 1993 unreleased track that is on the box set. He said, "If you listen to the lyrics all the way through, it’s seamless." Tench revealed that the song was inspired by Dave Peverett and Petty wrote the lyrics on the spot while the band worked on the music. Tench continued, "That’s the kind of writer he was. … I always say I’m an evangelist for Tom, because I think the world needs to know just how great he was."

Meanwhile, Heartbreaker member Mike Campbell said that he was surprised to hear the soul in Pettty's voice on another unreleased track "Lost In Your Eyes." He told Variety, "Tom is a rock 'n' roll singer, but this song is Otis Redding. He was a soul singer too. When he hits that high note — pure soul."

An American Treasure is due out on September 28th.