U2 hoping to release 14th studio album in March/April 2017

The bassist says he, Bono, The Edge and Larry have been working away on the follow-up to 2014’s ‘Songs of Innocence’ and plan to continue recording until the festive period.

"We've been working on a record and we've been humming and hawing on whether it's finished or not. We've decided it's not finished - we're going to work up until Christmas," Adam told RTÉ.

Pushed as to when they hope to release it, Adam added: "I wish we were a little bit more definite about our scheduling because people have been expecting it but it'll be out next year, maybe March/April. That's the plan, but I'm not confirming it."

U2 began formulating ideas for the album during down time on the iNNOCENCE + eXPERIENCE Tour in 2015.

The Edge told Q Magazine last year that their creative process reminded him of recording their 1993 album ‘Zooropa’,  which was outside their usual comfort zone.

“Brian (Eno) would love to see us making albums a bit more like that,” the Edge said, “Where we go, ‘You know what? We’re not going to second-guess any of this. Let’s just go for it.’ I think there’s a quality you get when there’s a certain momentum to the process.”

Bono also cited his 2014 cycling accident, where he suffered fractures to his face, shoulder and humerus, as also helping him formulate ideas.

“The gift of (my 2014 cycling accident) was that I had time to write while in the mentality that you get to at the end of an album,” Bono told Q. “There is a reason why all the great groups made their best albums while in and around touring, because the ideas have to come out of your head.”

2014’s ‘Songs of Innocence’ was released to iTunes customers at no cost in September 2014. A digital download and physical version came out a month later.