Bono opens up about 'excruciatingly' honest song-writing for Innocence

Bono wrote a love song for his mother on U2's latest album.

The 54-year-old singer paid tribute to his mum Iris on the band's 13th studio album, 'Songs of Innocence', and admits the autobiographical theme of the record was "excruciating" to write because he was determined not to leave anything out.