Willie Nelson and Sheryl Crow trade lines on "If I Were a Carpenter" on the Johnny Cash tribute album, We Walk The Line: A Celebration of the Music Of Johnny Cash, due in stores Aug. 7. Their duet is joined by a who's-who list of artists covering the late Man in Black's biggest hits, including Kris Kristofferson, Train's Pat Monahan, Ronnie Dunn, Jamey Johnson, Shooter Jennings and more. The album and its accompanying live DVD were recorded at Austin's Moody Theater back in April, where Johnny's friends, family and admirers gathered for an Austin City Limits Live concert dedicated to his music and legacy.

For Willie, being a part of this project was a way to pay tribute to one of his dearest friends, of whom he was a fan before they even met. Willie was working as a radio deejay back in the '50s when he first heard of the then-rising star, Johnny Cash.

"I always looked at John as somebody who had been there before me and who was doing it the way he wanted to do it," the Redheaded Stranger recalls. "He was one of the first rebels, the first outlaws that hit Nashville. I was a great fan of his not only for his music, but for his attitude." (Watch the interview with Willie in the first video player below.)

Willie's "Carpenter" collaborator, Sheryl Crow will forever be grateful for a rare and coveted honor on her résumé: Johnny Cash recorded one of her songs. The lauded tunesmith got the call from Johnny's son-in-law, saying that the country icon wanted to record Sheryl's anti-war song, "Redemption Day." Johnny recorded his haunting version of the song just three months before he passed away. It is featured on his posthumous album, American VI: Ain't No Grave.

"The conversation, as it unwound, was him really earnestly wanting to know what the song was about and why I had written it," Sheryl recalls of the conversation that would forever change her career. "If he was going to sing a song, in order for him to embody that song, he wanted to know exactly what the intention of it was. I think that's one of the reasons that when we hear him, we believe him." (See Sheryl's interview in the second video player below.)

Click here for more information about the Johnny Cash tribute album, which hits stores next Tuesday, Aug. 7.

Watch Willie Nelson Discuss Johnny Cash

Watch Sheryl Crow Discuss Johnny Cash