Willie Nelson's famous face is tanned and weathered. White whiskers increasingly dominate his two-day stubble, and streaks of grey colour the waist-length braid trailing down his back.
The country music legend is sitting on a bench seat inside a tour bus parked behind the bullpen at Diamond Stadium in Lake Elsinore, California, waiting to take the stage.
It's one stop on a summer tour of minor-league baseball parks with Bob Dylan and John Mellencamp, and Nelson displays a youthful vitality that many younger men would envy.
"I'm real lucky," this remarkable 76-year-old road warrior says, leaning forward and flashing an easy grin.
"My health is as good as it's ever been. My lungs are in good shape - and there are lots of people all over the world wondering how that could be, like Michael Phelps."
Nelson lets out an infectious laugh at the not-so-subtle reference to his celebrated affinity for pot and the Olympic swimming champion's troubles after photos of him inhaling from a marijuana pipe surfaced this year.
"So I'm in good health and I appreciate it."
When Nelson laughs, there's a gleam in his eye that's ageless; it's there too when he talks about reconnecting with the kind of songs he first heard as a boy growing up in Texas during the 1930s and '40s.
It was a time and place where the rural music of the South - then labelled "hillbilly music" - commingled on radio and in dance halls with the pop and big-band sounds most of the rest of the nation was enjoying, most prominently in the western swing sound pioneered by Bob Wills and His Texas Playboys.
"It all fits together," Nelson says.
"Western swing is just jazz. The musicians Bob had, the musicians Asleep at the Wheel has ... these are jazz musicians who can play anything; it just so happens they settled in on western swing."
Having recently passed the three-quarters-of-a-century mark, Nelson decided the time was right to return to that fertile trove of songs in American Classic, his new album.
The title describes both the Great American Songbook of pop standards he's drawing upon and the man himself, who is rivalled only by Merle Haggard for the title of country music's greatest living songwriter.
The field of pop-classic vocal albums has become crowded in recent years, with singers as wide-ranging as Rod Stewart, Michael Buble, Cyndi Lauper and Queen Latifah taking swings at songs largely written before they were born.
It takes moxie, to say nothing of serious vocal chops, to tackle songs famously recorded by Tony Bennett (Because of You), Ray Charles (Come Rain or Come Shine) and Frank Sinatra (Fly Me to the Moon) as Nelson does on American Classic.
"Of course I'm a huge Sinatra fan," Nelson says. "There are other guys who've made great versions of that song: Vic Damone, some of those guys ... It's probably been recorded a thousand times, but you always remember Sinatra."
On the album, Nelson is surrounded by a crew of jazz pros, starting with Joe Sample, the esteemed Crusaders' keyboardist who wrote the arrangements, and luminaries including guitarist Anthony Wilson, bassists Christian McBride and Robert Hurst, drummers Lewis Nash and Jeff Hamilton and organist Jim Cox.
Sample, also a Texan, has been a fan of Nelson for decades but had never worked with him before, which led to some trepidation about how to approach this project.
As the music was taking shape, he recalls phoning album producer Tommy LiPuma and telling him, "I have to be careful. I can't take Willie over the line [into straight-ahead jazz]. I know he understands what swing is, but he's not a jazz musician. And I'm not going to lay below that line and try to act like a country musician."
His fears were allayed when he got to Nelson's ranch outside Austin and spotted a collection of the complete recorded works of influential Gypsy jazz guitarist Django Reinhardt on Nelson's coffee table.
"When I saw that, I knew exactly what to do. I chilled out," he says. "I knew he was going to love whatever I came up with."
Nelson is nothing if not laid-back about revisiting songs that have been recorded by many of the greatest singers of the last century. He has been down this road before.
He concedes that he was ribbed for having had the temerity to cover Ray Charles with Georgia on My Mind. That was in 1978, when Nelson helped put the standards ball in motion with his Stardust album.
It wasn't the first by a performer outside the Sinatra-Bennett adult-pop world to explore that canon, but it quickly became one of the most popular and influential. It has sold more than 5 million copies, according to the Recording Industry Association of America.
"For me, it was a no-brainer," he says. "I thought, heck, these are great songs, we've got a great band, a great producer and arranger with Booker [T. Jones]. This has got to be a winner. But it wasn't that easy to sell the record companies on it. Back then we had to battle to get it out there."
Stardust constituted a major gamble at a time when Nelson was riding the crest of the outlaw country wave with his longtime collaborator Waylon Jennings.
A 90-degree left turn into the music of Hoagy Carmichael, George and Ira Gershwin, Duke Ellington and their peers was the last thing the public expected, despite the versatility and ambition Nelson had shown in themed concept albums that preceded Stardust, including Red Headed Stranger, Phases and Stages and his salute to Lefty Frizzell, To Lefty From Willie.
But it made total sense to Bruce Lundvall, the Columbia Records executive who signed Nelson to the label in the 1970s and now heads Blue Note Records, the jazz label that's releasing American Classic.
"When I signed him in the '70s, the first record he came in with was Red Headed Stranger," Lundvall said from his home in New York while recuperating from recent heart surgery.
"I called a meeting and told the staff, 'It may not sell, but it's Willie's dream record and we're putting it out.'
"I was way off base. It sold 3 million copies. Then he came back with Stardust and I thought, 'My God, how are they going to play this at country radio?' I was wrong again."
As for American Classic, another pet project for Lundvall, "I don't have expectations of it doing what Stardust did - that was unprecedented, and it became his best seller of all time. But I think it will do very well for us. ... The greatest thing for me is just being back in business with Willie Nelson."
Nelson says his heart always has belonged as much to jazz as to country.
Nelson explored the common ground between the genres on his 2008 album with New Orleans trumpeter Wynton Marsalis, Two Men With the Blues, an effort Marsalis spearheaded as head of the Jazz at Lincoln Center programme in New York.
It allowed Nelson to stretch out as both instrumentalist and vocalist, even beyond the signature elastic style he has exploited so successfully in country music.
That style is apparent in American Classic, particularly in Earl K. Brent and Matt Dennis' Angel Eyes, which presents a singer with some extraordinary melodic twists and turns.
When it's suggested that it often seems that he can sing anything, Nelson laughs again. "That's the problem sometimes," he says. "Sometimes you may have to rewrite on the spot - I think that's where jazz got started, because a guy forgot the melody."
Nelson's anti-establishment persona, along with philanthropic efforts including the annual Farm Aid concerts and conservation efforts such as his support of bio-diesel fuel and campaign against the slaughter of horses, have maintained his reputation as a maverick, which helps him as time goes on to win the respect of many beyond country music aficionados.
"One of the big things that caught my attention was after he moved to Nashville in the '60s, he and another Texan, Waylon Jennings, eventually told the Nashville people to go to hell, and they left," says Sample.
It's easy to wonder how he handles the pace he maintains.
American Classic is his fourth album in 2009 alone.
Once in a while there's a subtle sign that, as he sang to great comic effect on one of those albums for the Lost Highway label, I Ain't Superman.
"Fortunately and unfortunately, I'm out here a lot. It's good, because I like to play," he says, then coughs. "But at some point you're ready to go sit down and rest a while."
