In October, Haggard made his first foray into bluegrass music, releasing "The Bluegrass Sessions" on Del McCoury's record label. The set, which shot to No. 1 on Billboard's Top Bluegrass Albums chart, includes some new tunes, several reworked Haggard classics and some bluegrass standards.

"I went through my many, many stacks of songs and tried to find things that I thought would work well in these surroundings," Haggard said in a statement. "Bluegrass people are the salt of the earth, kind of a no-baloney audience. If you're going to play something and you're going to hook it, you'd better hook it good; it either has to be real funny or it has to be real serious."

The Grammy-winning performer sought help from Ronnie Reno and Marty Stewart, who plays guitar and mandolin on the album. The record, which was recorded in "living room"-style sessions at Ricky Skaggs' Tennessee studio, also features a duet with Alison Krauss on the Haggard classic "Mama's Hungry Eyes."

Of the result, Haggard said, "I really enjoyed doing it, and I hope this is just Volume One."

Last year, Haggard hooked up with fellow Country Music Hall of Famers Willie Nelson and Ray Price to tour behind their "Last of the Breed" album, which comprises fresh versions of country classics and a couple of new songs, including the Haggard-penned "Sweet Jesus."

During a career that spans more than 40 years, Haggard has released upwards of 65 albums and scored more than 40 No. 1 singles, according to his bio. In recent years, he's been honored with the Grammy organization's Lifetime Achievement Award and BMI's Icon Award.