Earlier today, after lunch at a favorite Nashville restaurant, Kings of Leon frontman Caleb Followill had an encounter that left him unsettled. "The valet guy, I see him a lot, he knows me," the singer says. "As I was leaving, he was like, 'Hey, man, do you guys still play? When I was in high school you were huge.' " The band -- which also includes Caleb's brothers Nathan (on drums) and Jared (guitar) and cousin Matthew Followill (bass) -- groans in unison. "I have nightmares that involve that exact scenario," says Jared. "What an asshole!" adds Nathan.

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"I had a five in my hand and I went, 'Nope!'" says Caleb, miming slipping a bill back into his pocket as they all crack up. "I switched it to a one."

What Caleb couldn't tell the valet, because the group had decided to keep it a secret, was that Kings of Leon definitely still make music -- and are about to return with their first album since 2013. Sixteen years and seven discs into their career, which vaulted the foursome from tiny clubs to stadiums as one of the biggest bands in ­contemporary rock n' roll, the Kings are putting the finishing touches on Walls, an ambitious statement of renewed purpose produced by Markus Dravs, best known for his work with Mumford & Sons and Arcade Fire. Early on, band members decided to keep news of the album to themselves until a couple of months before its Oct. 14 release, an effort to both take pressure off of the creative process and to make a bigger splash once the LP arrives. "We're not going the full Drake, day-of kind of thing, but we are definitely doing things differently," says Caleb. Adds Nathan, "People's attention spans are so much shorter now." (A few days later they tease the album by tweeting a cryptic video.)

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The Kings are gathered in a film production ­studio on the outskirts of town, where they're shooting album artwork the following day. Nathan's shaggy hair aside, they're clean-cut and bright-eyed and fit, sipping coffee and bottled water instead of the beer, whiskey and ­expensive wine they have a reputation for consuming in alarming quantities. (The Kings are all major ­foodies with investments in restaurants and real estate and founded Nashville's annual Music City Food & Wine Festival.) All four live in the area, and they share a nearby studio space. Says Caleb, "We definitely have a better, stronger ­relationship ­outside of music than we did in the past." To which Nathan shoots back, "Break out the Jameson and we'll tell you the real story."

Today's vibe is vastly different from the one surrounding the last couple of records. Their 2010 album Come Around Sundown sold 776,000 ­copies, according to Nielsen Music, marking a decline from 2008's Only by the Night, which featured the hits "Use Somebody" (a Billboard Hot 100 No. 4) and "Sex on Fire" and moved 2.5 million copies. Caleb claimed at the time to have been "checked out" for the whole cycle, which ended with him walking offstage midshow in Dallas and the band canceling the tour's ­remaining 26 dates as its members ­temporarily went their separate ways. 2013's Mechanical Bull sold only 347,000 copies. "There comes a point when you realize you've lost that passion and that hunger," says Caleb. "You're chastened and want to get it back -- and in order to get it back it's like, 'Forget about record sales, forget about the size of the venue you're playing, forget about any of that stuff.' "

What the group required was a major ­shake-up. It decided that its partnership with Angelo Petraglia, who produced all six of its previous LPs, had grown too safe. It sought out Dravs, who has a ­reputation for being intense; temporarily uprooted their ­families; and set out for Hollywood's Henson Recording Studios. "We said, 'Let's f--ing go to L.A., eat some sushi, get some sunshine,' " says Caleb. "The whole thing just felt a lot more organic." Still, Dravs proved to be a stern taskmaster, questioning every part of the band's music and routine. "He just said things that nobody had ever said to us," recalls Jared. "Like, 'I don't like that song, that's not good, we can move on from that.' " He had them endlessly replay parts, collectively write new verses on the fly and suddenly switch vibes. "He'd be like, 'OK, now play it like The Sex Pistols,'" says Jared. "And then you've turned a slow song into a fast one."

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The results range from the shimmering, U2-like anthem "Waste a Moment" to the spare, ­synthetic pulse of "Over." "One song would sound almost electronic and another would sound so ­broken-down," says Matthew. "But the way it all flowed together, we were just like, 'This guy is a genius.' "

These days all four Followills are married, and all but Jared are parents. They say the routines of ­marriage and fatherhood have been good for the band. (Caleb, who has a daughter, is married to Victoria's Secret model and Taylor Swift squad member Lily Aldridge.) "Our kids are always together, they all go to the same school," says Matthew. Jokes Nathan, "You can tell us apart from the other parents -- we're the ones smoking weed underneath the bleachers." And if things start coming apart again, the Kings can always call on advice from buddies like Bono and Eddie Vedder. "I remember really early on, Eddie told us to never tour Europe for more than three weeks," says Jared, "because that will break up your band."

"He also said to chase summer around the world," says Caleb. He pauses and cracks a big grin. "But we didn't realize he was talking about a groupie."

This article originally appeared in the Sept. 3 issue of Billboard.