In the two years since alt-J last played Brighton they’ve won the Mercury Music Prize, an Ivor Novello, sold more than a million records and heard their music grace everything from adverts to elevators.

And, as a pleasant aside, Miley Cyrus has even emerged as a fan of the band.

“She texts me now and again,” reveals drummer Thom Green. “She is a big fan of ours. In fact, I think she is just as star struck as we are with her. Obviously she is one of the biggest pop stars in the world, but at the end of the day she is a music fan and a musician, so she knows what she likes.”

The mutual love led Cyrus to ask Green to do a remix of the Pharrell Williams-penned 4x4 from the American former teen-star’s fourth album Bangerz.

When Green received the vocal stem from Cyrus’s single he recognised it was in the same key as a track he was working on. He chopped out 4x4’s refrain “I’m a female rebel” and pasted it into Hunger Of The Pine. The result sounds pleasingly sinister. It gives both the line and the alt-J song more weight.

“She liked it a lot,” adds Green, who says Cyrus is regularly in contact by text. “She is very incisive. And has loads of energy. She’s like, ‘oh that sounds dope, or that’s crazy, or I can’t way to show people’. She’s definitely crazy. Pretty full-on.”

The total opposite to the publicity shy alt-J, then, who chose an un-Googleable name and preferred to keep their faces away from press photos for a large part of their early career.

“We used the sample because it sounded good,” adds Green about Cyrus’s contribution. “We were weird about using it and that people might think we were trying to gain something from her fame, but we know we are not doing that. If nobody talked about it we would be fine.”

You get the impression alt-J wouldn’t mind if they never had to talk to anyone and could just get on with the business of making music.

The former Leeds University art students have already lost one member, blond-haired bass player Gwil Sainsbury who departed in January, after finding life on the road too much.

“Gwil didn’t like being away from home, not having control. He’s had a long-term girlfriend since before the band started and he found that hard.

“There are other things as well. We all met at art school and had things going on before the band. He felt like he hasn’t pursued what he wanted to pursue originally.”

Sainsbury had also earned enough to be comfortable and not have to go straight back onto the dole, as the band had previously done after leaving Leeds for Cambridge immediately after university.

The fall-out brought the band’s existence into question, but the remaining three members have returned more focused. On Monday they’ll release the follow-up to the Mercury-winning An Awesome Wave.

This Is All Yours is perhaps the most eagerly anticipated album this year. Despite being a man down, Green says there were no second album nerves.

“We never thought we wouldn’t be able to follow it up. We’ve always been confident. When Gwil left and it came to this second album the three of us tried to remember how well we worked together and took it quite relaxed. We had space in Hackney. We had all instruments in there and it was a big room in a warehouse.”

They refused to try a regimented work schedule.

“We weren’t nine to five. We’d go in mid-morning and talk for a while and figure out anything we were working on and wanted to go through. Sometimes we cracked on; sometimes we had no idea what we were doing and we would sit there not feeling it and just go home. That was the best attitude.”

Green’s workload has increased and his contributions have come to the forefront. It’s in tandem with his increasing expertise on production tool Ableton, which he taught himself on tour.

“I would have it set up in the studio and I might have a string arrangement going and Joe (Newman) would play to it.

“On Hunger Of The Pines I had that sonar sound at the beginning on loop. Joe had a guitar part he had been working on and it worked.

“We sat down and it wasn’t, ‘let’s write a track’ – it just happened.”

He created layers as he went, put in some beats and often replaced the live kit with programmed drums.

“When you programme beats it’s a very different way of writing than playing live kit.

“You can put in polyrhythms and things like that by dropping in high hats randomly which forms a beat you could never write if you were playing it live.”

It’s the same on Bloodflood pt.II, which starts with a tender piano line but is transformed by Green’s beats and samples.

Other parts of the new record, an impressive step forward for alt-J, are pastoral, with birdsong, church bells and three songs referencing the Japanese city, Nara.

So far the signs of success are positive. Green suffered the omen of a broken ankle on the day they finished recording.

“We’d just had a wrap-up dinner,” he says, laconically.

“It was perfect timing. We’d finished everything and had a few months off before starting rehearsals for the tour. It’s a good omen.”

• Support comes from Marika Hackman, who is on from 8.30pm.