Can the Kings of Leon make the Features rock royalty?

Little known outside Nashville, this week the Features play to 50,000 people in London.

Tonight Kings of Leon will not be supporting the Features. "It's not happening! It's not happening!" says Rollum Haas, who plays drums with the Features. He's been saying this a lot today. "I had to go on [classified ads website] Craigslist and say, 'This should not be advertised.' People were trying to pass off tickets for 200 bucks. 'They're not playing! Don't spend that much money!'"

We are in Nashville, Tennessee, where both bands are based. One of them, Kings of Leon, are among the world's biggest rock groups. They have sold millions of albums, won Grammys and Brits and headlined festivals across Europe. The other, the Features, have not. They've been plugging away for 12 years without much regard outside Nashville, and were dropped by their record label. But both groups are old friends, with Kings of Leon having taken the Features on tour several times. Tonight, the Features are playing Exit/In, a local venue Haas accurately describes as "a total dive bar". (It recently added an extension that increased its size by 25 per cent. New capacity: 300 people.) Word has gone out that Kings of Leon will be the surprise support act. Except the story turns out not to be true; how it started is something of a mystery. Though some of Kings of Leon will attend the show, their participation will extend as far as clapping the Features on from the balcony.

But if they're not lending their support musically, Kings of Leon have been supporting the Features in other ways. They have ' started a record label and signed them to it. As suggested by those people prepared to spend "200 bucks" on Craigslist, it could be the leg-up the Features need. "This is our second shot," confirms the bassist Roger Dabbs. "We've struggled for a while. We always seem to have been lurking in the shadows. Now it feels like people are actually paying attention." And so they should.

Kings of Leon's frontman Caleb Followill calls the Features "the best undiscovered band around. The first time I saw them play, you should have seen me – I was puking round the back; shaking. 'We can't follow these guys!' That's how I feel every time I see them."

Completed by singer/guitarist Matt Pelham and keyboardist Mark Bond, the Features play a boisterous indie-rock that might be described as Kings of Leon meets Kaiser Chiefs – though they're rather better than that sounds.

Distinguished by Pelham's songwriting that can be both poignant and sincere ("All I Ask", about a waning love) and Friday-night gonzo ("GMF", about genetically modified food), the band are musical Anglophiles whose love of Old Grey Whistle Test clips of the Kinks, XTC and Roxy Music is worn with some panache. A song such as the anthemic "The Temporary Blues" should be all over daytime Radio 1, but somehow it's not. And it's not as though people haven't noticed the Features before. "We've had so many bands come to support us in the UK," says Followill. "And they're the only band, where, every time we get an email it's, 'Please bring the Features back.' They're the only ones people have gone nuts for."

The band's 2004 album Exhibit A received glowing notices from NME, MOJO and Q. In 2007, they won the international Diesel:U: Music Award for Best New Band, voted for the public. When they were signed by America's Universal Records, home of Black Eyed Peas and Amy Winehouse, their time seemed to have come. But that relationship soon went south, according to Haas, thanks to Universal's enthusiasm for them to record a cover of "All You Need is Love" for adverts for the Chase Manhattan Bank, and the Features' enthusiasm to do nothing of the sort. "They wanted it as the lead-off single on the new record; to do this whole campaign," sighs Haas. "It would have been really awkward and bad."

Kings of Leon, meanwhile, have had the kind of career that's not supposed to happen any more – spending four albums broadening their commercial appeal without annoying the NME readers who liked them first.

Their 2008 single, "Sex on Fire", has had the dubious honour of being recognised as "an international karaoke anthem". Another, "Use Somebody", earnt the most prestigious Grammy – 2010's Record of the Year. "They were allowed to grow – something that's been lost in the music business," says Haas. "It really has." Now the Features, freshly signed to the Kings' new label Serpents & Snakes, hope they might be allowed to do something similar. The first fruit of the deal is Some Kind of Salvation, a re-release of an album the Features put out themselves in 2008.

The afternoon before the Features show, both bands gather in a bar called Losers. It's Followill's local. He lives across the road. (Taylor Swift, the huge American country star, lives downstairs; they're unlikely friends.)

Losers' own website describes it as a "no-frills watering hole". There's a poster of Hank Williams Sr tacked to one wall, a microphone set up in the corner and fairy lights round the bar. It's 2pm but Followill has been here awhile, chasing back his Michelob Ultras with shots of Patró*tequila. He's a little drunk. His bandmate, drummer Nathan Followill, soon joins him. The Features troop in, and a game of shuffleboard is soon up and running. The key to shuffleboard? "Drink enough," says Caleb. He is still reeling from the band's crowning glory at the Grammys in LA. "I have a few memories. I bought my mom a shot, then I fell down. She did it! She puked on my shoes, but she did it!

"We have an opportunity to give people a chance," Followill adds of the Serpents & Snakes label. "These guys have been around way longer than us, and they've made great songs, one after the other. "

I agree, I say. "The Temporary Blues" should be a huge song. "It is a huge song."

What I mean is, you don't hear it on the radio. "Unfortunately, you don't. Fuckin' radio. The Features could literally fart into their microphone and we could put it out."

They met in 2004 when Kings of Leon recruited the Features' soundman, who urged them to check the band out. Soon they were off touring together. "The Features are pretty quiet," Followill says. "Every now and then a band will challenge you to a party. And your show suffers 'cos you have to show this little fucking band you can party. But these guys... we play ping-pong. We talk." Pelham, who off-stage is thoughtful and a little reserved, nods along. Do Kings of Leon hope to sign up other bands? "Well, it depends," says Followill. "If we see something we like. They have to be good, though. I ain't putting out any shit."

It is an interesting time for this sort of thing. With the major record companies in a torrid place thanks to piracy and plummeting CD sales, some independent labels have grasped the nettle. In January, British indie label XL scored an American number one album with Vampire Weekend. Earlier this year, independent artists Dizzee Rascal, Friendly Fires and Animal Collective were all nominated for Brit Awards. (Dizzee won.) And later this very afternoon in Nashville, the White Stripes' Jack White will stage a gig by the blues-rockabilly act the Dex Romweber Duo at his own Third Man Records shop – anyone attending the free show is eligible for a copy of the live album, pressed up on vinyl on-site.

It is a home-grown approach Followill is all for. "The best thing that could ever happen to the music industry is to have artists control the label. You won't have some 85-year-old saying, 'Oh, I don't get it.' It's, like, 'Fuck you, that's 'cos you're 85 years old.' Hopefully one day these guys [the Features] will have a label and they'll be signing artists too."

The Features pose for some photos. Followill offers encouragement from the shuffleboard table. "Four assholes/ Hanging out in a bar," he sings across the room at them. "Fucking each other in the butt..."

His friends smile back inscrutably.

Nashville is called Music City with good reason. Just as the cliché suggests that every Hollywood waiter is a leading man waiting for their break, you don't have to spend long talking to your cab driver/shopkeeper/hotel receptionist in Nashville to discover they're a musician of some sort. "It's like Six Degrees of Kevin Bacon here," grins Haas. "Everyone knows each clique; everyone jumps up and plays with each other."

One afternoon the Features' affable manager Rory Daigle, who has tirelessly promoted his band for the past decade, drives me over to Bug Music, the world's largest independent country music publisher, owning the estates of Johnny Cash, Willie Dixon, Muddy Waters and Woody Guthrie. When Nathan and Caleb were starting out, before they got the band together, they signed to Bug as songwriters. Inside the anonymous white building, they've run out of wall space for gold discs – Wilco, Dixie Chicks, Rascal Flatts. This week they're celebrating another US number one with Nashville's own Lady Antebellum, one of 2010's break-out country-pop bands. Behind each door, there's any combination of artists and songwriters, hunched over acoustic guitars and laptops, putting in office hours writing songs. "It's like passing a kidney stone today," chuckles Roger Murrah, a veteran composer of hits for Kenny Rogers and Al Jarreau, and an inductee into the Nashville Songwriters Hall of Fame.

The Serpents & Snakes label has been developed in partnership with Bug. The Features are already earning the benefits of their modern marketing muscle: in January they got their song "Off-Track" on the TV show One Tree Hill, while "Lions" proved a download hit on the iPhone game Tap Tap Revenge 3. The same song can be accessed through Kings of Leon's website – spreading the word to their hefty fanbase. "Our hopes are that this will create a base where it will keep going and they can put out another record," Bug's CEO John Randolph tells me one evening over some "traditional Southern cooking"at Joe's Crab Shack. "It's not that I don't want them to have a number-one hit. It's just we don't want that pressure. It's more about a band willing to put the time in."

Indeed, the Features – who have gone through more than one line-up and two record labels since Pelham and Dabbs formed the group in eighth grade in Sparta, a rural Tennessee town with a population of less than 5,000, are already in a better position to do that. Having played four support slots with the Kings of Leon in Mexico last October, they've been able to buy a tour van. Soon Haas might be able to stop working at local record shop Grimey's.

At Exit/In, the Features are greeted like local heroes. Pelham becomes a strutting, spitting singer that his off-stage deportment scarcely suggests. And Haas is a mesmerising drummer, bouncing about and shaking his hair with Ready Steady Go! abandon. ("He's so pretty!" gasps a girl next to me.)

"That was a little bit of a work-out," says Pelham, afterwards. "All our songs are, like, two minutes long. We pack a lot in."

Five days later the Features are in London for three club performances. The Kings of Leon endorsement already seems to be working – the first show in Water Rats, King's Cross, is a sell-out. "Some of the music industry guys couldn't even get in," approves Daigle. "That's great from my point of view."

Lots of artists have started their own labels – from Elton John's Rocket Records and Madonna's Maverick, to hardcore punks Bad Religion and their Epitaph Records. They haven't always lasted. Given their day jobs, how will Kings of Leon keep theirs ticking over? "There's no guarantees in life," says Nathan Followill. "We hope this could be the start of something good, and help us get music out that we feel is great. In the perfect world, this time next year, we'll have three or four bands on there. Early in our career the Strokes did the same for us, took us on the road and talked us up in interviews – any time you can have a band stick up for you, that's great."

In testing times, that's true now more than ever.

The Features' UK tour runs from tomorrow to 7 July; they will be supporting Kings of Leon at their gig in Hyde Park on Wednesday. For details: myspace.com/thefeatures