The 65-year-old actor, author and recent Oscar host will release his second bluegrass album in March.
Martin spent months on the road performing with the Steep Canyon Rangers, and the bluegrass quintet backs him on Rare Bird Alert, which includes 13 new songs he wrote.
The album also features some impressive guest stars: Dixie Chicks and Sir Paul McCartney.
"It's very hard to believe," Martin said of having the former Beatle perform on his album. "I was a kid when I first heard Paul McCartney, and if you told me one day that he'd be singing one of my tunes, I'm still flabbergasted."
McCartney gives voice to a track called "Best Love," which Martin describes as "a love song, but it has a little humor in it."
The Dixie Chicks perform a "very emotional, heartbreaking song called 'You,'" Martin said, adding that they agreed to sing the tune before they'd even heard it.
"I was kind of disappointed because I really wanted them to hear the song first and like it," he said. "But they did like it and they did a great job."
Martin wrote the album while touring with the Rangers last year. He also penned a pair of tunes on the set of his forthcoming film, "The Big Year," where he was inspired by the Canadian landscape. The film, which stars Jack Black and Owen Wilson, also inspired the album's title.
"The movie is about bird-watching," Martin explained.
He first displayed his banjo skills on "Foggy Mountain Breakdown" with Earl Scruggs. Martin's first album of original music, The Crow: New Songs for the Five-String Banjo, won the Grammy for best bluegrass album in 2009.
Rare Bird Alert will be out March 15. Martin and his band will support the album with a national tour beginning in May.
A banjo player and bluegrass fan for nearly five decades, Martin said he loves the camaraderie of making music.
"You're always with somebody, whether you're on stage or in a recording studio, and my whole comedy career was solo," he said. "So that's a huge difference, a huge change for me and it's a positive change."