Four years ago he didn't have so much as a passport. Now, very polite Tennesseean Nathan Followill is trotting the globe with his two brothers and a cousin in Kings of Leon, he tells Tony Clayton-Lea

'How's it goin', Mr Ticket, sir? How is it with you? Fine? Good. Me? Yeah, I'm fine, too, buddy."

A polite query, genuine concern, getting your name wrong - it's a lovely way to start off any interview with a well-known rock band. Factor in the following and you'll know it's par for the course for the very friendly Kings of Leon.

The Followill brothers (Nathan, Caleb, Jared) and their cousin Matthew Followill are from a travelling Pentecostal background, born and bred on the poor side of the Tennessee divide. These boys were raised to be preachers, and they have the manners to prove it.

The Ticket (that's Mr Ticket, sir, to you) is talking to Nathan, drummer of Kings of Leon, and surely one of the nicest people in the history of rock music. He is telling your correspondent about the change in the band's fortunes; about how when they first came to notice almost three years ago (primarily on the back of their debut album, Youth and Young Manhood); about how their home territory ignored them - not even the massed ranks of the Tennessee State Police would arrest them.

These days in the US, following the healthy sales of last year's Aha Shake Heartbreak, and special guest slots with U2's Vertigo machine, Kings of Leon are swiftly emulating their European success.

"It's gettin' a lot better in America, for sure," says Nathan. "But there are prettier girls over your way. And Europe is so much more open-minded. The people over there don't have to wait on five million MTV kids to think it's cool before they'll think it's OK to like anything. If they like it, they like it, and if they don't they don't. Brutal honesty is a double-edged sword - good if they like you, and bad if they don't, but the U2 tour done a lot of good for us, that's for sure."

It isn't only the numbers that have changed for Kings of Leon; their debut of hickory-smoked, roughneck boogie rock subtly altered into something far more streamlined and mature by the time Aha Shake Heartbreak came along. What they do is still quintessentially American, which is all the more rewarding (for them and us) considering that when they were growing up between Memphis and Oklahoma City they didn't listen to anything beyond gospel music and old-time standards.

"It's not like we picked any one or two bands and tried to emulate them," reasons Nathan. "It's just one of those things where we had people all the time compare us with certain bands; that cracked us up because 90 per cent of the time we had never even heard of those bands - or any of the music. Our sound is definitely American, but that's just the way it came out. It's what we are, I guess."

The Followills' evangelical father was the reason why the family travelled up and down the Bible belt. (The band were formed in the aftermath of their parents' divorce, the name chosen as a tribute to their father, Leon.) Because they travelled from town to town, the family didn't own a house, but instead lived in a small camper van. Sometimes the Followills would stay in a town for a few months, depending on how Leon's preaching would go down; other times, they'd travel on after a few days. The longest they stayed anywhere was the Tennessee town of Millington, home to famous singer-turned-preacher Al Green and, believe it or not, Justin Timberlake.

Whatever the reception, whatever the duration of their visit, following the hellfire and brimstone would come the dancing and singing. Cue the makings of an empathetic group of musicians.

"Our day-to-day existence now and over the past couple of years compares quite well to when we were growing up," says Nathan. "Except instead of Kool Aid after church we now have wine after a show, and instead of preacher's daughters chasing us we have everybody else's daughters. The only difference, really, is that we get to sleep on a bus and watch TV in the back lounge, as opposed to fighting with my brothers in the back seat of the family vehicle because they're invading my personal two foot of space.

"We kinda feed off of what it was back then. Even five years back, we would never have guessed in a million years that what's happening now would be part of our lives. But it's very eerie how similar our past is to our present; it helped us out, it keeps us in our stride, keeps our heads on straight, because we know it can all be gone tomorrow.

"If it suddenly stopped? Man, I've seen the world five times over. Four years ago I didn't even have a passport, so that in itself is pretty cool. Also, the bands that we've met through our music and hung out with have been amazing. We came from nothing and we'll go back to nothing when this is over, so we'll enjoy it while it lasts. Hopefully, we'll find a girl that likes us enough to stay with us even when we're not playing in front of a bunch of people every night."

So you can take the boy out of mom's apple pie Tennessee, but not vice versa. No one wants to think that they're popular for anything other than because they're good guys, says Nathan.

"But the reality is that we're in a band, and a lot of people know us because of that. That's fine, because we can sort out the people who we know are genuine, and those we know that wouldn't have given us the time of day four years ago. Growing up on the road and being in a different town sometimes every week helped us within minutes to know who we liked - what kind of person they are, what they want from us, what their intentions are."

It all comes down to family, reckons Nathan, which is something you hear very few rock stars admit to (indeed, the Followill clan might just be the least obviously dysfunctional rock family in living memory). "I can only remember a life on the road spent with members of my family. We're all so close and tight we have a blast with each other. We went into music with an attitude of easy come, easy go, and that's our approach to everything. We're all pretty good at adapting to our environment."

So there you have it - Kings of Leon, southern fried nice guys who want to settle down (eventually) with women that'll take them for what they are, and not what they seem to be. The Ticket is about to ask Nathan the secret to his good guy persona, but he interrupts with a fond goodbye and a keen if somewhat out of character observation.

"Looka that chick! Gotta go, man. Hey, now, you put a coupla Guinness in the fridge for me, you hear, and I'll pick 'em up when I get to Dublin."

Kings of Leon are special guests of The Pixies at BudRising at Lansdowne Road, Dublin, on August 23rd. Other special guests include Teenage Fanclub, and Humanzi