The Cardiff septet had originally intended to make a short EP
Los Campesinos! are to release a 10-track 'interim album' and DVD on Monday.
The record, We Are Beautiful, We Are Doomed, comes eight months after their debut Hold On Now, Youngster was released.
The Cardiff septet had originally intended to make a short EP but told Newsbeat they decided to extend it after the songs "just kept coming".
Singer Aleksandra Campesinos! said: "There's been a lot of talk about this record coming out so soon after our debut.
"But we've been playing those songs for two years now so it kind of felt like we had new ambitions and new things that we wanted to try out in the studio.
"It just seemed like the right time to record an interim record. But we're still not treating it as a proper album because we're not releasing any singles from it."
The singer said that unlike their pop punching debut, the new record, is more mature and personal.
She said: "There's a lot more variety on this record, there's not just quick, punchy energetic pop songs that people associate with us, there's some slower numbers on there.
"Gareth (Campesinos!) came up with the lyrics when we were touring the US in May so it's very much a snap shot of a certain period of that time in his life.
The songs focus on thoughts and relationships in the sense that maybe there isn't the perfect solution and relationship for everyone
"The songs focus on his thoughts and relationships in the sense that maybe there isn't the perfect solution and relationship for everyone.
"It's kind of the disillusionment of that idea, like wanting to be a professional footballer and not making it."
To accompany the new album, the band also put together a behind the scenes DVD of their time on the road.
Aleks said drummer Ollie Campesinos! in particular contributed to the film's more comical moments.
"It's just us fooling around and being a bit stupid at times," she said.
"Ollie has all the best moments, the camera just loves him.
"There's this one bit when he tries to fit inside a water cooler, which is quite funny when he tries to get out because obviously it's full of ice.
"So he tries to stand up and he just falls on his a***.
"Ollie's the sort of person that if you try and say to him, 'Why don't you try and do that?', he'll try it."