“I think as a kid I always assumed America was a hot place but it’s very cold,” giggles George Ezra, reflecting on his own naivety during a break from his U.S. support tour with Irish singer-songwriter Hozier.

Selling out stadiums
Listening to the solo singer’s deep soulful voice you might assume that he’s a 50-something whiskered man who’s hollowed out his sound with years of cigar smoking. But his bluesy lyrics are more puerile than wizened pensioner: take “Cassy O’”, which, yes, is wordplay on the watch brand Casio, goes, “Well, I got my tracing paper / So that I could trace my clock / And the bastard face kept changing / And the hands, they wouldn’t stop."

Simplistic, juvenile even but catchy, the ditty is much like his hit “Budapest” with its crowd-pleasing, sing-it-back-to-me “Ohs” and “Oohs”. It’s no surprise that Ezra’s breakthrough ode to the Hungarian capital reached number three in the UK, while his debut record “Wanted on Voyage” – the name of which is taken from a sticker on his hero Paddington Bear’s suitcase – went platinum.

Ezra’s almost frustratingly modest about his achievements. He frequently qualifies and justifies his success – even though he’s now playing arenas like the 18,000-plus capacity Madison Square Garden, New York – with typical play-it-down Britishness: “The nice thing is it feels like everything happened quite naturally. I’ve done 100 capacity, a few hundred and it’s naturally grown. It’s not like I’ve been catapulted into some ridiculous situation overnight.”

Sam, Ed, and George
Actually, he was one of last year’s biggest selling UK artists, bettered only by the likes of Sam Smith and Ed Sheeran. His label, Columbia Records, must be more than pleased at his profitable and levelheaded professionalism, which, like Ezra’s voice, belies his age. He’s a fresh-faced old soul, too, when it comes to the follow-up of his debut album saying, “The one thing I’ve learnt with this campaign is not to push yourself… like, you know, it’s only fun if it comes naturally – I’m not going to force it.”

The 21-year-old from Hertford, England, is “keeping a lid” on any kind of rock ‘n’ roll raucousness, after he got “pretty ill at the end of last month” at around the time of the Brit Awards in February. Certainly for now, Ezra is focused on “keeping his head down” and getting through his two-month U.S. tour without too many scars, although he admits that he’s had a fair few in the past.

While studying songwriting at the BIMM Institute in Bristol, he managed to crack his head open on a wall as he ran late to a lecture by a visiting Ramone. By the time he went to the hospital, it was too late to prevent the scar above Ezra’s right eye, which apparently hurts when it’s cold, from becoming permanent. That wasn’t his only close call: Ezra recalls a time when traveling on a London train that he stuck his head out of the carriage window like an excited puppy when a train rushed by in the other direction, narrowly missing his head. “That was f---ed; I didn’t like that all. I try to keep my head inside when I can,” he affirms, half-chastising himself.

Budapest or bust
That was before his year’s inter-railing around Europe which inspired much of his first album, including the track “Budapest”, the city which he never made it to but has visited since. And why didn’t he make it? “I stopped off in Sweden and it was the first time that I had like a proper night out. And I just woke up feeling very rough and the journey to Budapest wasn’t easy, so I didn’t bother,” Ezra says.

Indeed, it’s not all clean living with Ezra but he won’t be partaking in the student rite-of-passage pilgrimage to the beaches and mushroom parties of Thailand. “Definitely not,” he remonstrates. “I won’t be doing that s---. I’ve got some time off at the end of this America trip, so I’ll probably go to somewhere in Europe,” he explains before slipping back to living relentlessly in reality, adding, “I’m never going to see it all, so I’m happy to see as much as I can.” Oh, George.

George Ezra in concert:

New York City
April 22, 8 p.m.
Webster Hall
125 E. 11th St., 212-353-1600
www.websterhall.com