Catfish & the Bottlemen have always loved their trips to Glasgow.

Now the Welsh rockers are writing a song about why they've fallen for the city.

The group, who've penned guitar anthems like Kathleen and Cocoon, play a sold-out gig at the Barrowland on Tuesday, and singer Van McCann has taken the city to his heart.

"I've actually just finished writing a song called Glasgow, about a night out on Sauchiehall Street," he says.

"It might be for the next record.

"After the last time in Glasgow I wanted to write a tune for the people that came to see us - we've never had anything like this, so I wanted to write an acoustic tune about falling in love with the city.

"Whenever we play it live it's going to take the roof off the place.

"We've been told the Barrowland is the best gig in the world, so it's going to be chaos.

"T In The Park last year was a game-changer for us, we'd done Scottish gigs before that were wild, but never to that level."

2014 was a year that changed everything for Catfish. Formed by Van while in his teens, they'd been gigging for several years without getting anywhere (at one point the singer mentions not even selling 50 tickets for a gig in Derby)

But after landing a record deal, their album The Balcony proved a huge hit, packed full of straightforward sing-a-long rock.

It might not considered hip or trendy, but the tunes were certainly catchy, and Catfish's audiences have kept growing and growing.

They've toured America, gained a celebrity fan in Ewan McGregor ("one of the most interesting guys you could meet", says Van) and next Tuesday's Barrowland date had to be upgraded from the O2 ABC because of demand.

A likeable interviewee prone to brash statements, Van has far higher ambitions, though.

"We do want to take it to football stadiums," he says.

"Growing up you'd get bands like that every couple of years, like the Arctic Monkeys or Oasis and we want to fill those big gigs, and give a new generation of kids a band to believe in.

"The bigger the room the bigger we get our sound, so every time that happens I get more adrenaline, and I'm already full of it, so you can imagine what I'm going to be like with thousands watching us."

Some bands might want to bask in the success of their first album, but Van clearly isn't keen to slow things down.

He's already written the second record, and they're currently planning when to hit the studio.

"The quicker I come up with songs then the quicker we can get another record made," he says.

"We do take this seriously, even if we're having fun - we really do want to play stadiums, we don't want to disappear.

"You're lucky to get to a second album or a third album now, because all these modern bands have no ideas - they'll get signed off of one song, go to LA to record an album, start partying and waste it. We won't do that."

That means the band are already eyeing up an even bigger sound for the future, keeping with their obvious determination to build on their debut.

"Everyone thinks the new songs sound five years ahead of the last album," adds Van.

"The songwriting's matured and the sound will be bigger - it'll be arms up in the air rock n roll that's massive and explosive. I think it's going to move things forward."

Despite Van's undoubted confidence, the 22-year-old admits that he was starting to lose faith they'd ever break through before they were offered a record deal.

"There was doubt just before we got the record deal," he adds.

"We'd been going eight years, and it seemed like it wasn't happening.

"Then we got the chance of making a record, and anything from there was a bonus - all we can do is give it our best.

"If you aim to be the biggest band in the world then you've got something to aim at.

"If we'd been aiming to just be as big as Bloc Party then we've already done it, and that's what a lot of bands do now - they aim for Brixton Academy, and then go, 'oh, I'm done now'.

"We don't want that, we want to be bigger and bigger."

Catfish & the Bottlemen, Barrowland, Tuesday, sold out.