U2 fans received a cryptic letter teasing news on Monday (21.08.17).

The Irish rock band have sent out pieces of paper featuring the words ''Blackout ... It's clear who you are will appear ... U2.com'' and a line, which reads: ''U2 will announce [blank] on [blank].''

Over the text, which appears to be an abstract from William Blake's collection of poems 'Songs of Innocence and Experience', the inspiration for their last album 'Songs of Innocence', is a silhouette of a boy and girl holding hands.

Several fans have taken to social media to share the mail, but still have no idea what it's meant to mean.

The 'With or Without You' rockers recently admitted choosing songs for their album has been an ''ordeal''.

Bassist Adam Clayton - who is joined by Bono, The Edge, and Larry Mullen Jr. in the group - said: ''We've an abundance of great ideas and it's really about identifying what to finish and how to finish it.''

The Edge added: ''That's the gift and the curse of this record. The ordeal is getting all four members to agree on the same dozen songs.''

Meanwhile, the band insist they don't feel a ''responsibility'' to raise political issues in their work - but still want to ''have a go''.

The Edge said: ''I don't know if we feel a responsibility so much.

''Just that there are moments where you just feel like, 'Wow, someone has got to write a great song about this and hopefully it will be us, so let's have a go.'

''Coming out of the post-punk era, we were inspired by The Clash, Patti Smith, Television - innovators who also had one foot in the worlds of poetry and literature and the other in political activism. That's deeply embedded in our band.

''One of the reasons we write a song is to crystallise something of significance for ourselves and, hopefully, other people.''

However, Adam is unsure whether rock music is now the right platform on which to take a stand because the political climate is so complicated.

He said: ''I think the world has changed a bit. I'm not sure that within the culture that music is the best medium any more.

''There's so much noise out there anyway, people saying this, that and the other, that I think music is a little bit insecure as regards what its role is in these situations.''