GREENFIELD — In about an hour, they’ll take the stage as one of the main attractions on the bill. At the moment, though, in a dressing room at the Green River Festival last Saturday, they are first and foremost close friends and mutual admirers. The fact that they have a band together nearly seems like an afterthought.
Puss N Boots, a homespun folk-country trio consisting of Norah Jones, Sasha Dobson, and Catherine Popper, got off to a rather humble start. In 2008 they began gigging in dive bars around New York, playing in front of friends for the simple pleasure of live performance and interpreting songs they loved.
“We were just playing shows and coming together as our schedules went along,” Dobson says backstage, one eye closed as she applies mascara. “It was just about playing music and not having an agenda of any kind.”
“The future wasn’t planned out,” adds Jones, who has sunk into a sofa, feeling relieved that her newborn slept for most of the drive from New York. “The band originally started as me and Sasha learning to play guitar together. It took a minute for it to jell, but it’s been jelled for quite a few years. We just never really played enough to think about making a record until now.”
“We didn’t rehearse either, so every gig was very loose, but in a very musical way,” says Popper, holding a curling iron.
Six years later, they finally got around to recording their debut album, “No Fools, No Fun,” released earlier this week. A short run of tour dates brings them to the Sinclair, in Cambridge, for a sold-out show on Thursday, followed by a Saturday appearance at next weekend’s Newport Folk Festival, which is also sold out.
“It was never stressful because it was loose and nobody was coming but our friends,” Jones says, “but I was always sweating by the end because I would think, ‘Ahhh! I don’t know what I’m doing!’ ”
That was a big part of the impetus for Puss N Boots. They issued a challenge: Each member would learn a new instrument for the band. For Jones and Dobson, that meant picking up guitar (and also drums for Dobson), and Popper sharpened her chops on pedal steel guitar.
Jones is the known quantity in the band, the Grammy-winning singer and songwriter whose debut, “Come Away With Me,” was the runaway success of 2002. Dobson is an eclectic solo artist with a sultry voice and torch-singer allure. And Popper is a badass bassist known for her work with everyone from Ryan Adams to Jack White to Grace Potter & the Nocturnals.
On the new album and in concert, no member steps into the spotlight. There’s not a leader in the band, per se. At their Green River Festival performance, they interacted like three high school friends jamming on someone’s back porch. They stood in a single line — Jones and Dobson on guitar, Popper on bass — with each singing lead at some point and Dobson occasionally on drums.
By most accounts, their early shows were pretty freewheeling, enough so that one particular blogger deemed them “crazy sloppy.”
“I loved it,” says Joel Hamilton, who recorded the band at Studio G in Brooklyn and also mixed and engineered the new album. “All of the musicality was there, but it was being voiced on instruments that they weren’t entirely comfortable on. They all play within their means. They walk the tightrope together, and if you get out on the tightrope, you’re not going to wiggle it with two other people on there with you.”
“No Fools, No Fun,” which takes its name from a line in a song they cover (Rodney Crowell’s “Bull Rider”), is the sound of three accomplished musicians venturing beyond their comfort zone. It has a warm, lived-in charm that sometimes comes across as slight, but still heartfelt. Of the 12 songs, seven are covers and five originals (two apiece by Popper and Dobson, one by Jones).
The cover selections come mostly from the folk and country canons, from “Leaving London,” a Tom Paxton tune they learned from Doc Watson’s version, to Wilco’s “Jesus, Etc.” They also tackle Neil Young’s “Down by the River,” featuring a surprisingly unhinged guitar solo by Jones.
Their offstage chemistry is as palpable as it is on record. When asked how they met, Popper tells the story of how they were at a wedding, and Jones, who was hammered, approached her and said, “You’re really hot.”
“I did?!” Jones shrieks in disbelief. “Now I’m embarrassed. I don’t remember this.”
“It was after your [first] record came out, and I loved your record and I wanted to tell you,” Popper says.
“I was probably nervous to talk to you because you’re so tall and beautiful,” Jones shoots back.
The three of them seem to have arrived at a consensus about Puss N Boots’ mission. As long as they’re enjoying it, the audience probably will, too.
“It’s the opposite of someone imposing their music onto the band,” Dobson says. “It’s an amazing situation where we egg each other on. Catherine had a couple of songs brewing, and we were like, ‘Great! Let’s do them tonight!’ That’s how you make [expletive] happen. Because 99 percent of the time it completely works out.”James Reed can be reached at firstname.lastname@example.org. Follow him on Twitter @GlobeJamesReed.