The remastered Joshua Tree features several unreleased demos from The Joshua Tree Sessions. Bono recently added new vocals to one of them, 'Wave of Sorrow', and this week talked about the inspiration for the song. Watch our exclusive video.

Interviewed in New York, Bono explains that Wave of Sorrow 'was one of the songs from the Joshua Tree sessions that we never finished... a song that was trying to describe experiences that myself and Ali had when we were working in Ethiopia during the famine.'

The track is one of several rare and previously unreleased cuts which feature on the bonus audio CD, which comes with the deluxe edition of the re-released album.

Watch the clip below
Check our mini-site for all the details on The Joshua Tree 2007